Various fixes for loader and imprved S3 Client driver

What's Changed

• Respect custom loader by @zorn-v in #481
• Fix symfony 6.1 deprecation by @zorn-v in #482
• update configuration reader to use v3 of league flysytem by @Justin-Jordan in #485
• Allow no-credentials for S3 Client by @alexbusu in #486

New Contributors

• @Justin-Jordan made their first contribution in #485
• @alexbusu made their first contribution in #486

Full Changelog: 12.1.3...12.1.4