[8.12] feat(slo): new slo architecture (#172224)

[kibanamachine]

Backport

This will backport the following commits from main to 8.12:

• feat(slo): new slo architecture (#172224)

Questions ?

Please refer to the Backport tool documentation

[elasticmachine]

Pinging @elastic/obs-ux-management-team (Team:obs-ux-management)

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: fd762cf

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
observability	546	567	+21

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
@kbn/slo-schema	128	144	+16

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
observability	1.1MB	1.1MB	-14.1KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
observability	102.6KB	102.6KB	+28.0B

Saved Objects .kibana field count

Every field in each saved object type adds overhead to Elasticsearch. Kibana needs to keep the total field count below Elasticsearch's default limit of 1000 fields. Only specify field mappings for the fields you wish to search on or query. See https://www.elastic.co/guide/en/kibana/master/saved-objects-service.html#_mappings

id	before	after	diff
slo	10	11	+1

Unknown metric groups

API count

id	before	after	diff
@kbn/slo-schema	131	144	+13

async chunk count

id	before	after	diff
observability	21	22	+1

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @kdelemme