[FEATURE] Update existing extension point registration to permit both adding and removing

[dbwiddis]

Is your feature request related to a problem?

Part of #356

What solution would you like?

Update the following registration models to permit removing additions when an extension is uninstalled

• RestController (see Add methods to RestController to test Rest Paths and unregister them OpenSearch#6395)
• Settings
• Actions

Keep the above list updated as new extension points are implemented per #315