Update FTR to support running tests against specific serverless project types

[lukeelmers]

In #150616, Spencer added serverless config files specific to different project types. Ultimately we'll want to have FTR support for running Kibana in each of these serverless "modes" so that we can add tests for each project type (or possibly rerun some existing tests in each of the configs).

There are a few things we are hoping to accomplish here:

1. an easy/clear way to run FTR with each of the configs
2. a path for teams to run their tests against particular project types
3. a plan for running these tests in CI

Regarding (3), we should discuss what makes the most sense without having a big impact on CI times. We may not need to run these tests on all PRs if the PRs don't make changes to the config/serverless* yml files, but that's up for debate. We could also consider skipping checks on PRs and running them only on merges to main. Or maybe a combination of the two.

--

cc @clintandrewhall @thomasneirynck @kobelb @rudolf as we discussed this recently

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[elasticmachine]

Pinging @elastic/kibana-qa (Team:QA)

[lukeelmers]

Pinging @elastic/appex-qa for feedback as well -- I'm not sure where this discussion should fall between Ops & QA

[wayneseymour]

@lukeelmers I've heard from Sophie that we do indeed have at least one es serverless to start testing against.
Can you point me to it?

[pheyos]

We (AppEx-QA) will look into this and related requirements around testing against ES stateless. We'll report back once we have a proposal.

[lukeelmers]

Thanks @wayneseymour and @pheyos! For reference, these PRs added the original Serverless-specific config files:

• [serverless] add support for loading serverless specific config locally #149878
• [serverless] split serverless config files #150616

I believe they are just working in dev mode now, but one of the PRs mentioned that @jbudz might have plans to enable these for CI testing regions. We are still working out how exactly we'll want the config mechanism to work in production (cf #152395).

[pheyos]

There are a few things we are hoping to accomplish here:

1. an easy/clear way to run FTR with each of the configs
2. a path for teams to run their tests against particular project types
3. a plan for running these tests in CI

Update: I think items 1 and 2 are covered by #157166. For item 3, we have a plan and work on this in progress.

[pheyos]

I think with #162673 merged, this issue can be considered done.