Allow services migrations

[Jibbarth]

Hi there 👋

I am migrating an old Sylius app from v1 to v2, upgrading also symfony to SF7.4.

During upgrade, I noticed that my old migrations raised an exception as the ContainerAwareInterface does not longer exist.

I tried to migrate migrations to services, enabling this in my doctrine_migration config

# config/packages/doctrine_migrations.yaml

doctrine_migrations:
    enable_service_migrations: true

It works well BUT it didn't see anymore any migration from sylius core and plugin.

The Factory added in the PR will automatically retrieve migration as service if registered with tag doctrine_migrations.migration, and if not retrieve any, fallback to the current factory.

It's allow to having some migration as service, and kept the whole migration discovery process from core/plugin working.

⚠️ This doesn't require enable_service_migrations in your config. If you leave it enabled, Doctrine Migrations will ignore the factory override and use its default service provider instead, so no core/plugin migration will be visible.