Add loki-stack chart

[torstenwalter]

This adds the loki-stack chart from the loki repository to this repo.

It includes the existing history. You can verify it yourself by checking the history for individual files as in the example:

$ git log --oneline charts/loki-stack/Chart.yaml
8ec129f adjust README to new chart repo
943dfe9 Helm Chart: Fix schema of logstash default values (#3004)
96f71ba [Helm Chart Loki] Add needed k8s objects for alerting config: (#2965)
e60700c update loki-stack to use latest logstash version (#2940)
efd34c5 Allow to define the ingress service port (#2789)
58aec3e helm chart: Fix broken logo (#2651)
0cd01e9 Update helm and jsonnet to new release (#2809)
cbe0794 Fix linting errors and use of deprecated repositories (#2742)
51a57d2 Promtail: (and also fluent-bit) change the max batch size to 1MB  (#2710)
eafc9b0 [Promtail] enables configuring psp in helm chart (#2659)
6c3d803 Add support for PV selector in Loki statefulset (#2554)
03b944e updating images to 1.6.0 (#2504)
51cb8a9 Add optional secret to pull Docker image in fluent-bit chart (#2489)
8b96ffd promtail: enable externalIPs support for syslog (#2490)
0c66cfb Fix regression in chart name (#2406)
760bf16 Loki Logstash Plugin (#1822)
1912567 Render loki datasources even if Grafana is disabled. (#2197)
2379cab helm: Add loadBalancerIP option to loki chart (#2238)
d837f94 BUG: add missing namespace in ingress object (#2205)
2e793d7 Adds the ability to have a pull secrets for Promtail. (#2141)
0f1c7bb helm/loki-stack: render loki datasource only if grafana is enabled (#2086)
23102eb Support Prometheus on a sub-path in Grafana config (#2099)
e864f1e updating all the images to 1.5.0 release (#2100)
cc1bc31 Change image tag from 1.4.1 to 1.4.0 in Helm chart (#2015)
f0becad added extraCommandlineArgs in values file (#1981)
2f22bdb Reverting helm changes which were included in Cortex 1.0 vendor upgrade because it resulted in us pushing an unstable helm.
dfc0778 bumps helm to keepalive-master after cortex vendoring (#1937)
79234cb updating helm and ksonnet to 1.4.1 updating Fluent Bit to correct image
f403d40 [helm loki/promtail] make UpdateStrategy configurable (#1898)
b53037c updating helm and ksonnet for 1.4.0 release
0bd7c10 Add extraMount, extraVolumeMount to promtail helm chart for systemd-journal (#1871)
a7857a8 Helm/loki-stack: refresh default grafana.image.tag to 6.7.0 (#1825)
4b496db Move default port for Loki to 3100 everywhere. (#1838)
eabe9ae [promtail helm chart] - Expand promtail syslog svc to support values (#1731)
23b3ca4 [promtail helm chart] Enable support for syslog service (#1617)
f5e842a Loki stack helm chart can deploy datasources without Grafana (#1688)
b2c1287 Added support for imagePullSecrets in Loki Helm chart (#1632)
f7cf65c Promtail Helm Chart: Add support for extra environment variables (#1529)
bd6e080 added ability to configure kernel setting fs.inotify.max_user_instances through init container to resolve issue with too many open files (#1620)
0b5c3de [loki helm chart] added ingress (#1585)
d4ca3b3 Helm/loki-stack: refresh default grafana.image.tag to 6.6.0 (#1590)
0312960 Helm/loki-stack: add template for the service name to connect to loki (#1587)
2faa377 helm: Allow setting 'loadBalancerSourceRanges' for the loki service (#1553)
43ca2e1 updating to 1.3.0 release
e9e3392 Allow extra command line args for external labels like hostname (#1530)
f4e1e78 helm: add podsecuritypolicy for fluent-bit (#1506)
d367078 helm: support adding init containers to the loki pod (#1336)
53c4f6c v1.2.0: update helm and ksonnet (#1389)
3563f1c Updating version numbers for 1.1.0 release
fa5e81d Update loki helm chart to support service account annotations (#1341)
7a639ab updating helm and ksonnet to version v1.0.0 (#1292)
1b9171d helm: update default terminationGracePeriodSeconds to 4800 (#1257)
d5093f2 helm/loki-stack supports k8s 1.16 (#1238)
727fdee Helm path update (#1061)
c776952 update versions to new release
92f3a94 Helm: Fix the reference error of loki/loki helm chart (#1056)
47283fb Add release name to prometheus service name. (#1174)
d774d0a rollback fluent-bit push path until we release 0.4
7173bcd helm: Add support for passing arbitrary secrets (#1111)
7fe67cf Feature: Add extra containers to loki helm chart (#909)
1a7a35e fluent-bit shared object go plugin (#847)
fce1d99 Helm: Remove default value of storageClassName in loki/loki helm chart (#1058)
c6b0658 helm chart: Add missing operator to promtail (#967)
6e47577 Bump chart versions
b40eb43 bump chart
4fca8ec update  helm and ksonnet to 0.3.0
f4238a2 Reorder relabeling rules to prevent pod label from overwriting config defined labels
61c077f release: update ksonnet and helm charts to version v0.2.0
336df41 fix grafana image tag by pinning it (#835)
5a9c666 Helm chart: Added service monitor (#824)
424f36e Helm: Be able to customize the Namespace (#830)
60e2839 fix helm lint issue
28b5f28 Merge branch 'master' into reduce-config-option
81c54b7 updating versions for loki v0.1.0
eb5aa8b Merge branch 'master' into reduce-config-option
d5e2251 Limits: Reject entries based on age set in limits (#631)
5db6cfd Switch Loki to StatefulSet (#585)
d535827 ksonnet changes for running loki in single binary (#622)
4602da5 Merge branch 'master' into reduce-config-option
fb034dd This add make target to deploy a dev version using helm (#586)
481929f Added namespace to helm install notes (#617)
016a78e Also bumping lok-stack version which needs to be done if the loki or promtail chart versions are changed (#612)
717fe6e Merge branch 'master' into reduce-config-option
06ca1fb Helm: Allow custom pipeline stages (#580)
09d633b add optional PodDisruptionBudget to helm chart (#515)
ddabd7a Support CRI 1.14+ directory change
8e67e52 Add scrape config for control plane static pods
f56cb64 Add option (#528)
fe36262 bump up chart version
99c53c6 Configurable Loki scheme in helm file, with optional basic auth (#494)
1159f5c Bumped chart versions
4ecbdde Update chart version
2229932 Helm: Allow custom loki config
d3e45c9 Add a /ready endpoint to promtail
3cb048a Fix missing volume after refactor
eb80f2c Add loki-stack helm chart

Filtering the history was did a great trick on reducing the history size.

In addition to migrating the repositories the following things have been done:

• all linting errors in Markdown files have been resolved
• minor version of the charts has been increased
  The goal of this is to publish a newer version of the charts from this repo. I choose to increase the minor version so that it's possible to increase the patch version to deprecate the existing charts and point to the new location.
• READMEs was adjusted to take the new helm repository location into account.

Note:

• I disabled validation of maintainers as "Loki Maintainers" is not a valid GitHub username.
  Here one should decide if one explicitly want's to name all maintainers or refer to a github team which exists.
  Not sure if GitHub teams could be resolved, but we could at least use it in CODEOWNERS file.
• DCO check is failing as history was imported. We should ignore it for this PR.

Part-of: grafana/loki#2593

[slim-bean]

LGTM! Amazing work @torstenwalter