Add `doctrine/orm` 3 support

[franmomu]

Subject

This PR tries to add support for doctrine/orm 3

I am targeting this branch, because these changes are BC.

Changelog

### Added
- Support for `doctrine/orm` 3

The CI should be modified to allow installing doctrine/orm 3

[franmomu]

We need https://github.com/doctrine/data-fixtures/pull/452

[greg0ire]

The next blocker seems to be https://github.com/doctrine-extensions/DoctrineExtensions/issues/2708

[franmomu]

The next blocker seems to be doctrine-extensions/DoctrineExtensions#2708

Yep, that would take a bit longer I think, I'll try to help with that

[VincentLanglet]

Hi @franmomu, what about following the same strategy than https://github.com/sonata-project/SonataDoctrineORMAdminBundle/blob/4.x/.github/workflows/test_orm_3.yaml ?

gedmo/doctrine-extensions is an optional dev dependency, it should be a blocker for the ORM 3 support.

[amacrobert-meq]

Is there anything I can do to help this PR along? This bundle is holding up an ORM upgrade on our end, so I'm happy to help if I can.

[VincentLanglet]

Is there anything I can do to help this PR along? This bundle is holding up an ORM upgrade on our end, so I'm happy to help if I can.

Basically, we need green tests.

If you want you can recreate the same PR and add a github actions similar to https://github.com/sonata-project/SonataDoctrineORMAdminBundle/blob/4.x/.github/workflows/test_orm_3.yaml

Instead of removing AuditBundle you remove the doctrineExtensions.

[franmomu]

I found some time to try to work on this, I've tried to remove some deprecations (related to accessing new mapping objects as array), but there should be more.

Not sure if I can keep working on this in the following days, so if anyone wants to continue with this, feel free to do it.

[franmomu]

I think this is ready to be reviewed, the SimpleThings\EntityAudit\Utils\ORMCompatibilityTrait tries to avoid deprecations triggered by ORM 3 accessing to mapping objects as array.

At first, I've used a getMappingValue method for almost everything, and then I've starting using specific methods (getMappingColumnNameValue, getMappingNameValue, etc) to be able to be more specific about types.

[VincentLanglet]

Do you want me to merge/release or should we wait ? @franmomu

[franmomu]

since I've change some things, it would be nice to have another approval, I've requested reviews 🤞

[phansys]

Thank you @franmomu!

[VincentLanglet]

Go for the release https://github.com/sonata-project/EntityAuditBundle/pull/628