Remove usage of the IdentifierService from any non-legacy code

[akhenry]

Summary

The IdenfitierService is doing translation between persistence spaces and namespaces. This distinction has never been supported by our modern API and was deprecated years ago.

This change may cause compatibility issues for any legacy custom persistence providers that were implicitly relying on the identifierService to perform translations between the '' and 'mct' namespaces. If this is the case, it is recommended that plugins are updated to use the current Open MCT API, which requires a single unambiguous namespace to be specified.

Any database-specific compatibility issues with existing data that may use a mixture of namespaces (as Couch did) should be handled in the plugin itself. The Open MCT Couch DB plugin can be used as an example.

[akhenry]

Testing Notes

This involves no new features but does affect the fundamental functioning of the Object API and the Couch DB adapter.

• Verify that the tree is being populated with objects from Couch DB,
• Verify that new Couch DB objects can be created,
• Verify that existing Couch DB objects can be modified,
• Verify that existing Couch DB objects can be deleted.

[shefalijoshi]

Unable to create new objects, but that might be a side-effect of #4615

[shefalijoshi]

Apart from the LegacyObjectAPIInterceptor.js, it appears that identifierService is not being used in any non-legacy code.
Closing.

[michaelrogers]

Verified change during Testathon 2022-01-06 on release/1.8.3.

Observed populated tree, created a new domain object and modified and deleted existing domain objects.