[8.x] Revert backported AssetInventory plugin (revert #202827) (#204641)

## 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:

- #202291

which was backported with:

- #202827

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

- #202862

So I'm deleting and reverting each change manually.

### Checklist

- [x] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

### Risks

No risk at all.

.github/CODEOWNERS

@@ -52,7 +52,6 @@ packages/kbn-apm-types @elastic/obs-ux-infra_services-team
 packages/kbn-apm-utils @elastic/obs-ux-infra_services-team
 test/plugin_functional/plugins/app_link_test @elastic/kibana-core
 x-pack/test/usage_collection/plugins/application_usage_test @elastic/kibana-core
-x-pack/solutions/security/plugins/asset_inventory @elastic/kibana-cloud-security-posture
 x-pack/test/security_api_integration/plugins/audit_log @elastic/kibana-security
 src/platform/packages/shared/kbn-avc-banner @elastic/security-defend-workflows
 packages/kbn-axe-config @elastic/kibana-qa

docs/developer/plugin-list.asciidoc

@@ -470,10 +470,6 @@ The plugin exposes the static DefaultEditorController class to consume.
 |WARNING: Missing README.
 
 
-|{kib-repo}blob/{branch}/x-pack/solutions/security/plugins/asset_inventory/README.md[assetInventory]
-|Centralized asset inventory experience within the Elastic Security solution. A central place for users to view and manage all their assets from different environments.
-
-
 |{kib-repo}blob/{branch}/x-pack/plugins/banners/README.md[banners]
 |Allow to add a header banner that will be displayed on every page of the Kibana application
 

package.json

@@ -191,7 +191,6 @@
     "@kbn/apm-utils": "link:packages/kbn-apm-utils",
     "@kbn/app-link-test-plugin": "link:test/plugin_functional/plugins/app_link_test",
     "@kbn/application-usage-test-plugin": "link:x-pack/test/usage_collection/plugins/application_usage_test",
-    "@kbn/asset-inventory-plugin": "link:x-pack/solutions/security/plugins/asset_inventory",
     "@kbn/audit-log-plugin": "link:x-pack/test/security_api_integration/plugins/audit_log",
     "@kbn/avc-banner": "link:src/platform/packages/shared/kbn-avc-banner",
     "@kbn/banners-plugin": "link:x-pack/plugins/banners",

packages/kbn-optimizer/limits.yml

@@ -5,7 +5,6 @@ pageLoadAssetSize:
   aiops: 18000
   alerting: 106936
   apm: 64385
-  assetInventory: 18478
   banners: 17946
   bfetch: 22837
   canvas: 29355

tsconfig.base.json

@@ -98,8 +98,6 @@
       "@kbn/app-link-test-plugin/*": ["test/plugin_functional/plugins/app_link_test/*"],
       "@kbn/application-usage-test-plugin": ["x-pack/test/usage_collection/plugins/application_usage_test"],
       "@kbn/application-usage-test-plugin/*": ["x-pack/test/usage_collection/plugins/application_usage_test/*"],
-      "@kbn/asset-inventory-plugin": ["x-pack/solutions/security/plugins/asset_inventory"],
-      "@kbn/asset-inventory-plugin/*": ["x-pack/solutions/security/plugins/asset_inventory/*"],
       "@kbn/audit-log-plugin": ["x-pack/test/security_api_integration/plugins/audit_log"],
       "@kbn/audit-log-plugin/*": ["x-pack/test/security_api_integration/plugins/audit_log/*"],
       "@kbn/avc-banner": ["src/platform/packages/shared/kbn-avc-banner"],