Add scpsl-egg

[EsserGaming]

Description

This PR adds my egg that I've been working on (off a fork of another's) for a while now, and I believe it's ready to be published to the pterodactyl egg repo. Obviously it may need some extra changes due to the guidelines, and I'm willing to work on that. So this will be a draft for now, until I can prepare it further.

My original repo is: https://github.com/EsserGaming/scpsl-egg

TODO:

• Write README for new egg
• Figure out what the new folder should be called
• New folder, use current name
• Change install image to ptero yolk
• Change container image to ptero yolk

Checklist for all submissions

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you tested and reviewed your changes with confidence that everything works?
• Did you branch your changes and PR from that branch and not from your master branch?

New egg Submissions

1. Does your submission pass tests (server is connectable)?
2. Does your egg use a custom docker image?
   • Have you tried to use a generic image?
   • Did you PR the necessary changes to make it work?
3. Have you added the egg to the main README.md and any other README files in subdirectories of the egg according to the alphabetical order?
4. Have you added a unique README.md for the egg you are adding according to the alphabetical order?
5. You verify that the start command applied does not use a shell script
   • If some script is needed then it is part of a current yolk or a PR to add one
6. The egg was exported from the panel

[EsserGaming]

I'm curious if I need to make a PR for a yolk since the only dependency I need installed is ffmpeg, but I didn't notice a requirement for first party container images. Please correct me if I'm wrong.

I ended up using ghcr.io/ptero-eggs/yolks:debian_trixie which supports all the features.