IBX-7485: Implemented custom Filesystem that handles corrupted filepaths

[barw4]

Proof of concept PR

Question	Answer
JIRA issue	IBX-7485
Type	bug
Target Ibexa version	v3.3
BC breaks	no

This PR overrides league/flysystem's Filesystem class so it handles already existing files with broken paths gracefully.

I intentionally overrode only some of the methods of the original class as we still should disallow uploading files with broken names, this should fix the issue with broken names already existing in the filesystem/db.

Another idea (skipping broken files): #400

Checklist:

• Provided PR description.
• Tested the solution manually.
• Provided automated test coverage.
• Checked that target branch is set correctly (master for features, the oldest supported for bugs).
• Ran PHP CS Fixer for new PHP code (use $ composer fix-cs).
• Asked for a review (ping @ezsystems/engineering-team).

[sonarcloud]

Quality Gate passed

The SonarCloud Quality Gate passed, but some issues were introduced.

1 New issue
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[alongosz]

We rely on that filesystem in many places (nfs, multirepo) and regression coverage is still not what we aim to, so it's best to avoid touching it.

Favoring #400 over this.