Improve schema metadata for Search Kit

[colemanw]

Overview

Improves the relevance of entities listed in Search Kit by:

1. Excluding entities from disabled components.
2. Designating some entities as not searchable.

Before

1. All entities returned from APIv4 Entity::get().
2. No metadata about which entities are searchable.

After

1. APIv4 Entity::get() excludes entities from disabled components.
2. Search kit excludes API entities annotated @searchable false.

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[colemanw]

@seamuslee001 @eileenmcnaughton @totten this PR is mostly just adding metadata. It'll go stale quickly.

[seamuslee001]

Makes sense to me MOP

[seamuslee001]

@colemanw test fail relates

api\v4\Entity\ConformanceTest::testEntitiesProvider

[colemanw]

Right. That's because the test suite doesn't enable all components by default. Should be fixed now.