feat: Optional max_file_size for parsing form files

[khadrawy]

Summary

Limiting the size of file being uploaded in case the storage is limited or some business logic can't handle certain size.

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.