[DoctrineBridge] add `DoctrineLoader`, which extracts information from Doctrine ORM

[Warxcell]

Q	A
Branch?	6.2
Bug fix?	no
New feature?	yes
Deprecations?	no
Tickets	Fix #41227
License	MIT
Doc PR

Needs help from someone to make this configurable in FrameworkBundle. (Opt-in probably, and desired format for date and time).

Just noticed the Static analysis failure - but return value from method seems useless, cause it's not used anywhere - and because of that, I'm unsure what should be returned ?

https://github.com/symfony/symfony/blob/5.4/src/Symfony/Component/Serializer/Mapping/Factory/ClassMetadataFactory.php#L50

[OskarStark]

I fixed the typo in the PR title, please change it in the commit message: "extacts" -> "extracts". Thanks

[Warxcell]

What's the issue with