GHA for validating the database schema

[MarioRadu]

We should consider adding a new github action that will validate the database structure using doctrine's command :

php bin/doctrine orm:validate-schema --skip-sync The --skip-sync option it's required here because we sync the database using migration files and running tjhe command without it will result in an error.

[alexmerlin]

FYI: There already is a WIP branch for this: https://github.com/dotkernel/api/tree/issue-292

[arhimede]

@MarioRadu please create a PR https://github.com/dotkernel/api/compare/5.0...issue-292