Add default `RepositoryConfigurationExtension.getModuleIdentifier()` method

[mp911de]

The module prefix is being used in various places, however the implementation is only available on the abstract RepositoryConfigurationExtensionSupport class and not on the RepositoryConfigurationExtension interface. We should provide a default method for easier consumption. This change requires an update of all RepositoryConfigurationExtensionSupport implementations that define a protected getModulePrefix method.

[jxblum]

Not opposed to this change, but what was just wondering what was the main motivation driving this change (now)?

[mp911de]

This is to split out the change so we can merge the the ManagedTypes change without the need to touch all modules.

[jxblum]

Ah, right. Thx, @mp911de.

[odrotbohm]

In the triage call today we came to the following, slightly different conclusion:

• The method is supposed to be named getModuleIdentifier() as – while there are currently methods called getModulePrefix() in abstract base types of the interface – the value returned is not the module prefix, it's the module's name but used as a prefix, primarily to build the name for the named queries properties file.
• The default implementation will lower-case the getModuleName() and defensively replace spaces with dashes, although no official module actually uses spaces in their module names.

The introduced getModuleIdentifier() should then be used as alternative to the getModulePrefix() methods in the individual store's configuration extension base classes.

[odrotbohm]

This is in place now. As indicated in 75387bb, modules are encouraged to move away from implementing getModulePrefix() (they still need to keep the implementation around, still), rather implement getModuleName() to return a human-readable name of the module and potentially additionally getModuleIdentifier() in case the translation implemented in RepositoryConfigurationExtension doesn't match the current arrangement.