Update to 2.2.0

- To ensure we have the HydratorManager
- To allow us to remove the set/getIdentifierName() methods from the
  ResourceController
Remove obsolete methods

- No longer need to override these as of 2.2.0
Re-tooled MetadataMap/Metadata to use HydratorPluginManager

- Allows sharing hydrator instances
- Allows having custom hydrator instances
Update MetadataMap factory

- Injects HydratorPluginManager when creating MetadataMap instance
Refactored HalLinks to use HydratorPluginManager

- Passed in via constructor (factory in Module class enforces this)
- addHydrator() now checks string $hydrator arguments against the
  composed hydrator manager, and pulls from there if a match is found.
Ensure HydratorManager is properly injected by factory

- Required changing some test expectations; the hydrators are not
  actually shared by default. Additionally, did not need the invokable
  services any longer, and could not query the SM, but rather the HM,
  for hydrators.
Updated documentation

- to reflect changes to hydrators
CS fixes

- per php-cs-fixer (trailing whitespace)
Merge branch 'feature/hydrator-manager' into develop

Close #77