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
• IBX-8470: Upgraded codebase to Symfony 6 content-forms#78
• IBX-8470: Upgraded codebase to Symfony 6 notifications#12
• IBX-8470: Upgraded codebase to Symfony 6 design-engine#31
• IBX-8470: Upgraded codebase to Symfony 6 http-cache#54
• IBX-8470: Upgraded codebase to Symfony 6 rest#138
• IBX-8470: Upgraded codebase to Symfony 6 search#50

Description:

This PR bumps Symfony to v6 with necessary and optional codebase upgrades. Updated also PHPUnit configuration.

Key changes:

• [Composer] Bumped Symfony packages requirements to ^6.4
• [Composer] Bumped jms/translation-bundle to ^2.4 for Symfony 6 compat.
• [Composer] Dropped obsolete dependency on ibexa/ci-scripts
• Aligned Symfony Bundle extension points code with Symfony 6
• Refactored Legacy naming for Ibexa Core default settings
• [Composer] Dropped cyclic dependency on ibexa/fieldtype-richtext
• [Security] Aligned DefaultAuthenticationFailureHandler with Symfony 6
• Upgraded Symfony Forms extension point code to Symfony 6
• Improved DateTime Formatter code quality
• Aligned Symfony Validator extension point code with Symfony 6
• [PHPStan] Removed resolved issues from the baseline
• [DI] Autoconfigured controllers for Symfony 6
• [PHPUnit] Migrated configuration from a deprecated schema

QA:

Sanities in the form of regression tests.

Documentation:

No documentation required.

[sonarcloud]

Quality Gate passed

Issues
0 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