Fix mongodb changeset

[IonBazan]

This PR tries to fix the entity/document listeners by:

• Relying on Doctrine\Persistence events
• Using getObject() from the event itself instead of using Adapter
  - Adding getChangeSet() to the adapter itself so it can be customized

The MongoDB ODM part is a bit poorly tested as many classes are final which makes it really difficult to test.

[IonBazan]

@garak I think this is now ready to go - just the PHPStan errors needs some fixing but most of it doesn't seem to be related to this PR itself.

[garak]

Are we forced to change an interface? If so, we need to update the changelog with proper instructions. If approved, this change can't be published before the next minor version.
Moreover, the errors reported by phpstan look related to proposed changes.

[IonBazan]

Unfortunately, this AdapterInterface change is mandatory:

• getObjectFromArgs() was removed because we can rely on getObject() on the event itself so the method becomes obsolete
• getChangeSet() was introduced to provide an adapter between MongoDB ODM (getDocumentChangeSet()) and ORM (getEntityChangeSet()) which is the core of the issue solved by this PR

If we really don't want to touch the interface, we could shift this logic to the listener itself but that would defeat the purpose of using the adapter, especially that the adapter is marked as @internal since v1.19.0.

I will take a look at PHPStan errors again and solve them in next commit 👍🏻

[IonBazan]

This error is ignored because the object returned from getObjectManager() is an instance of Doctrine\ODM\PHPCR\DocumentManagerInterface (https://github.com/doctrine/phpcr-odm/blob/master/lib/Doctrine/ODM/PHPCR/DocumentManagerInterface.php) but we are not installing this package so phpstan can't analyze this.

[garak]

@IonBazan I'm not against the interface change, but this PR should include an update to changelog

[garak]

Any news?

[IonBazan]

@garak sorry, I think the issue that this PR was initially trying to fix has been solved in v1.19.1. I will rebase it and simplify the interface changes then.

[IonBazan]

@garak I think this is now ready for a review again. Let me know if the changes still make sense after the changes from v1.19.
I've also added some UPGRADING.md notes to highlight the changes in AdapterInterface.

[garak]

Do you mind proposing the same changes on the master branch?