IBX-8470: Upgraded codebase to Symfony 6

[alongosz]

Caution

This is a part of bigger set of changes, to be merged together when ready

• ❗ Remove TMP commits before merge ❗

🎫 Issue	IBX-8470

Related PRs:

• IBX-8470: Upgraded codebase to Symfony 6 core#447
• IBX-8470: Bumped Symfony to version 6 doctrine-schema#27

Description:

This PR bumps Symfony to v6 with necessary codebase upgrades.

Key changes:

• [Composer] Forced PHP >= 8.3
• [Git] Added missing src/contracts directory
• Bumped Symfony packages requirements to ^6.4
• [Composer] Bumped psy/psysh to ^0.12.4 which supports Symfony 6
• [Composer] Dropped dependency on ci-scripts standalone app
• [Composer] Dropped abandoned behat/mink-goutte-driver
• [Composer] Dropped direct dependency on PHP CS Fixer
• Aligned RetryChoiceListFactory with Symfony 6
• [Tests] Aligned form tests with Symfony 6
• [Tests] Aligned codebase with upgraded version of psy/psysh
• [PHPStan] Removed resolved issues

QA:

Up to QA to decide.

Documentation:

No documentation required.

[sonarcloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud