[8.x] Revert backported AssetInventory plugin (revert #202827)

[albertoblaz]

Summary

Clean-up all "Asset Inventory" plugin code from the 8.x branch.

Motivation

It was decided in the weekly meetings not to backport any work related to Asset Inventory because it's a new feature. However, this decision was made after I had already shipped the first PR that introduced all the minimal required boilerplate:

• Create the "Asset Inventory" Kibana Plugin #202291

which was backported with:

• [8.x] Create the "Asset Inventory" Kibana Plugin (#202291) #202827

I couldn't auto revert the merge commit because of this refactor PR that was merged in between:

• Sustainable Kibana Architecture: Move modules owned by @elastic/kibana-cloud-security-posture #202862

So I'm deleting and reverting each change manually.

Checklist

• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• The PR description includes the appropriate Release Notes section, and the correct release_note:* label is applied per the guidelines

Risks

No risk at all.

[github-actions]

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[elasticmachine]

Pinging @elastic/kibana-cloud-security-posture (Team:Cloud Security)

[kapral18]

Please do not merge this pull request. We disabled auto-merge because we are trying to merge a big PR as part of sustainable architecture migration which is impossible with ever increasing stream of backports. We will resume the automerge after our PR is merged. Reach out to #sustainable-kibana-architecture for more info.

[kapral18]

Auto-merge has been re-enabled. Thank you for your patience. :heart

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 0e5bfae

Failed CI Steps

• FTR Configs #32

Test Failures

• [job] [logs] FTR Configs #32 / Cloud Security Posture Findings Page onboarding Vulnerabilities - clicking on the No integrations installed prompt action button - install CNVM: navigates to the CNVM integration installation page

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
assetInventory	16	-	-16

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
assetInventory	6	-	-6

Async chunks

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

id	before	after	diff
assetInventory	1.2KB	-	-1.2KB

Page load bundle

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

id	before	after	diff
assetInventory	3.1KB	-	-3.1KB

Unknown metric groups

API count

id	before	after	diff
assetInventory	6	-	-6

async chunk count

id	before	after	diff
assetInventory	1	-	-1

ESLint disabled line counts

id	before	after	diff
assetInventory	5	-	-5

References to deprecated APIs

id	before	after	diff
assetInventory	1	-	-1

Total ESLint disabled count

id	before	after	diff
assetInventory	5	-	-5

History

• 💚 Build #261537 succeeded 67bdd64

cc @albertoblaz