Make the annotations package optional

[mbabker]

Fix #2554
Fix #2683

With all of the known dependencies to the Annotations package reviewed and adjusted, it should now be practical to make it an optional package. And that's what this PR accomplishes.

It'd be hugely beneficial if folks would test this in downstream applications, especially if this package is the only reason doctrine/annotations gets installed in their application, to make sure the features they are using are not broken (I've done it in an app using the ORM plus the loggable and sortable extensions, but that's a very small amount of test coverage). To apply this PR, update your composer.json as appropriate with this info:

{
  "repositories": [
    {
      "type": "vcs",
      "url": "/~https://github.com/mbabker/DoctrineExtensions"
    }
  ],
  "require": {
    "gedmo/doctrine-extensions": "dev-optional-annotations as 3.15.0",
  }
}

[codecov]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (2ba8f94) 79.38% compared to head (f6032db) 79.34%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/Mapping/ExtensionMetadataFactory.php	70.58%	5 Missing ⚠️
src/Mapping/MappedEventSubscriber.php	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2735      +/-   ##
==========================================
- Coverage   79.38%   79.34%   -0.04%     
==========================================
  Files         162      162              
  Lines        8498     8506       +8     
==========================================
+ Hits         6746     6749       +3     
- Misses       1752     1757       +5     

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[franmomu]

Sorry for the late reply, let's merge it since it will be easier to test, thanks for the effort you are putting into this @mbabker!