feat(slo): manage slo state

[kdelemme]

📝 Summary

Resolves #148148

This PR adds two new routes for managing SLOs state: enable and disable.
When enabling an SLO, we set the enabled flag to true and start the related transform.
When disabling an SLO, we set the enabled flag to false and stop the related transform.

Nothing is done if the slo is already in the requested state.

🥼 Manual testing

1. Create an SLO
2. Disable it twice
3. Enable it twice

enable slo

curl --request POST \
  --url http://localhost:5601/kibana/api/observability/slos/f342de10-9cdb-11ed-b784-37f76896fdb8/enable \
  --header 'Authorization: Basic ZWxhc3RpYzpjaGFuZ2VtZQ==' \
  --header 'kbn-xsrf: oui'

enable slo

curl --request POST \
  --url http://localhost:5601/kibana/api/observability/slos/f342de10-9cdb-11ed-b784-37f76896fdb8/disable \
  --header 'Authorization: Basic ZWxhc3RpYzpjaGFuZ2VtZQ==' \
  --header 'kbn-xsrf: oui'

[elasticmachine]

Pinging @elastic/actionable-observability (Team: Actionable Observability)

[CoenWarmer]

Changes LGTM!

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: a9c0c4d

Metrics [docs]

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	73	75	+2

Async chunks

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

id	before	after	diff
observability	572.7KB	572.7KB	+10.0B

Unknown metric groups

API count

id	before	after	diff
@kbn/slo-schema	73	75	+2

History

• 💚 Build #103770 succeeded b480f17
• 💚 Build #103156 succeeded a94b57b
• 💚 Build #102960 succeeded a177f0413cd079545b5e96873476601e9367b882
• 💛 Build #102772 was flaky 9532c1bdfe1b3cd72b0db8e5e57dc8cc382533bb
• 💔 Build #102755 failed dd2e54cfa3a36b55d4686cd892bc9a0535fa30c7
• 💔 Build #102743 failed ab2d678662370ff6ee7cea9eb9c7179468d35486

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

cc @kdelemme