refactor: PropertyDescribers

[DjordyKoert]

Refactor to the behaviour of the property describers:

• Automatic tagging for PropertyDescriberInterface with nelmio_api_doc.swagger.processor. This makes it easier for users of the bundle the create their own property describers.
• Deprecate NullablePropertyTrait in favor of using a property describer service.
  • Implement a nullable property describer as replacement
  • Implement PropertyDescriberAwareTrait & PropertyDescriberAwareInterface to allow 'chaining' of describers
• Refactor PropertyDescriberInterface dependency injection by no longer requiring to pass an array of describers
  • Potential BC: ArrayPropertyDesciber & CompoundPropertyDesciber constructor removed
    • Quick search through github shows no impact to other codebases for this

ObjectModelDescriber changes:

• Deprecate injection of PropertyDescriberInterface[] in favor of a single PropertyDescriberInterface
• Require symfony/deprecation-contracts to ease deprecations

Additional change:

• add $context (context from Model) parameter to methods of PropertyDescriberInterface
  • Prevents potential recursion when chaining property describers *no longer needed for supports method
  • Allows better property generation using model context. Potential use cases:
    • Added UUID property describer #2098 Better doc generation for uuid https://github.com/symfony/symfony/blob/7bbc9be7ea7d607fa901edb2068c2cea13d24978/src/Symfony/Component/Serializer/Normalizer/UidNormalizer.php#L53-L62
• Fixes Allow arbitrary array instead of throwing UndocumentedArrayItemsException #2175 by removing the need to document an array
• Fixes $context not being passed to nested classes on properties

[DjordyKoert]

Remove this to prevent users from unintentionally injecting this in unrelated services. Use the PropertyDescriberAware instead