Add 'all' extras group

[DeltaWhy]

Feature request: add an extras group called 'all' to pyproject.toml to enable all optional features. This is a convenience feature to allow running uvx copyparty[all] instead of listing each group individually. If new features/dependencies are added in the future, users won't have to change their start command to get them.

[9001]

that's a neat idea, but I'm not sure it should be "literally all"; for example, if you have FFmpeg installed, then that will do a better job than mutagen at reading tags, so you don't want mutagen in that case... And even though libvips is faster than asking FFmpeg to create thumbnails, I suspect that FFmpeg would use less RAM / be more reliable.

but having an "all" option which enables pillow, pyftpdlib, pyopenssl, argon2 and pyzmq shouldn't be too bad I think.