Proposal: Split oxygen sounds

[Benjamin Port]

Hello,

Currently all plasma sounds came from oxygen, even if you use breeze theme you still need to install oxygen package in order to have sound notification for example.

That's why I will suggest to split oxygen repository. Current oxygen repository will keep everything except sounds. And a new one oxygen-sounds will have them.

This will allow to not depend on the whole oxygen theme anymore, and allow more minimal setup

My action Plan (if you are ok with the split):
- Ask sysadmin to create the new repository
- Do the split

Best regards,
Benjamin