Add command to import github events from gh archive

[DavyGab]

Main Updates:

1. GitHub Events Import:

   • Functional app:import-github-events command with date filtering
   • Command : php bin/console app:import-github-events YYYY-MM-DD
   • Leveraged GithubEventImporter for event handling.

2. Repository Refactoring:

   • Added methods to handle actors, repositories, and events with secure transactions.
   • Conflict resolution for duplicate entries.

3. Technical Improvements:

   • Added symfony/http-client as a dependency.

Testing:

• Command successfully tested, including edge cases.
• Validated with PHPUnit (unit and functional tests).

Future Enhancements:

• Asynchronous processing with Symfony Messenger.