Move all entity type REST tests to the providing modules

Problem/Motivation

Drupal 8's REST support was developed in parallel with many other major changes in Drupal 8. Consequently, we ended up with a REST module that had little test coverage.

We fixed that in #2737719: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method → + #2824572: Write EntityResourceTestBase subclasses for every other entity type. → . Then we ensured that we'd never regress: #2868035: Test that all core content+config entity types have functional REST test coverage → .

The next step is to ensure that every module owns its REST test coverage, to instill responsibility.

Proposed resolution

Move \Drupal\Tests\hal\Functional\EntityResource\Node\NodeHalJsonAnonTest to \Drupal\Tests\node\Functional\Rest\NodeHalJsonAnonTest, etc.

Remaining tasks

None.

User interface changes

None.

API changes

None.

Data model changes

None.