Support OSM progressive traffic shifting in Flagger

[johnsonshi]

• OSM Kustomize file and patch yaml files
• OSM Metrics Observer with request-success-rate and request-duration based on osm-specific prometheus metrics
• OSM Router (using SMI v1alpha2 router)
• OSM option in Flagger main.go/init() --mesh-provider option
• OSM option in Flagger helm install
• OSM example yaml files for osm-canary.yaml and osm-canary-steps.yaml in artifacts/examples
• E2E tests for OSM working with Flagger (canary promotion test, canary rollback test, canary promotion steps test)

[codecov-commenter]

Codecov Report

Merging #955 (11375b6) into main (e2b08eb) will decrease coverage by 0.12%.
The diff coverage is 28.00%.

@@            Coverage Diff             @@
##             main     #955      +/-   ##
==========================================
- Coverage   56.88%   56.76%   -0.13%     
==========================================
  Files          71       72       +1     
  Lines        5861     5886      +25     
==========================================
+ Hits         3334     3341       +7     
- Misses       2032     2046      +14     
- Partials      495      499       +4     

Impacted Files	Coverage Δ
pkg/metrics/observers/factory.go	0.00% <0.00%> (ø)
pkg/router/factory.go	0.00% <0.00%> (ø)
pkg/metrics/observers/osm.go	46.66% <46.66%> (ø)
pkg/canary/config_tracker.go	83.40% <0.00%> (ø)

---

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[johnsonshi]

Related to openservicemesh/osm#1700

[johnsonshi]

I have decided to write and include OSM Flagger docs in a separate PR immediately after this one (as this PR is getting large), which is why I reversed my docs additions: 003f1b3

[johnsonshi]

@stefanprodan // @draychev - The E2E tests are currently failing not due to issues with this PR, but due to issues with Traefik's recent release. Running the Traefik E2E test run script (from latest upstream main commit) on a newly-created kind cluster fails as seen below.

~/Dev/src/github.com/fluxcd/flagger(main) » kind create cluster                                                                                                                                    johnsonshi@DESKTOP-AQ60TOB
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.21.1) 🖼
 ✓ Preparing nodes 📦
 ✓ Writing configuration 📜
 ✓ Starting control-plane 🕹️
 ✓ Installing CNI 🔌
 ✓ Installing StorageClass 💾
Set kubectl context to "kind-kind"
You can now use your cluster with:

kubectl cluster-info --context kind-kind

Not sure what to do next? 😅  Check out https://kind.sigs.k8s.io/docs/user/quick-start/
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » kubectl cluster-info --context kind-kind                                                                                                               johnsonshi@DESKTOP-AQ60TOB
Kubernetes control plane is running at https://127.0.0.1:51503
CoreDNS is running at https://127.0.0.1:51503/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » git checkout main                                                                                                                                      johnsonshi@DESKTOP-AQ60TOB
Already on 'main'
Your branch is up to date with 'origin/main'.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » git remote -v                                                                                                                                          johnsonshi@DESKTOP-AQ60TOB
origin	git@github.com:johnsonshi/flagger.git (fetch)
origin	git@github.com:johnsonshi/flagger.git (push)
upstream	https://github.com/fluxcd/flagger.git (fetch)
upstream	https://github.com/fluxcd/flagger.git (push)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » git fetch upstream                                                                                                                                     johnsonshi@DESKTOP-AQ60TOB
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » git rebase upstream/main                                                                                                                               johnsonshi@DESKTOP-AQ60TOB
Current branch main is up to date.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
~/Dev/src/github.com/fluxcd/flagger(main) » ./test/traefik/run.sh                                                                                                                                  johnsonshi@DESKTOP-AQ60TOB
>>> Creating traefik namespace
namespace/traefik created
>>> Installing Traefik
"traefik" already exists with the same configuration, skipping
Release "traefik" does not exist. Installing it now.
Error: unable to build kubernetes objects from release manifest: unable to decode "": resource.metadataOnlyObject.ObjectMeta: v1.ObjectMeta.Annotations: ReadString: expects " or n, but found 9, error found in #10 byte of ...|io/port":9100,"prome|..., bigger context ...|metheus.io/path":"/metrics","prometheus.io/port":9100,"prometheus.io/scrape":"true"},"labels":{"app.|...
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

[stefanprodan]

@johnsonshi I have fixed the Traefik e2e tests, please rebase with main and force push.

[johnsonshi]

It seems like Github Actions is facing an outage right now across different repos.

[johnsonshi]

@stefanprodan This should be ready now.

[stefanprodan]

@johnsonshi this looks great, can you squash/rearrange your commits please. Thank you!

[johnsonshi]

Hi @stefanprodan, just squashed my commits. Thanks!

[johnsonshi]

Hi @stefanprodan, hopefully this can be merged soon! Thanks for all your comments in my PR.

[stefanprodan]

LGTM

Thanks @johnsonshi 🥇

PS. Are you going to add an OSM tutorial next?

[johnsonshi]

Yes @stefanprodan, going to add the osm tutorial next.