add spt egg, modify EFT readme and main readme

[cocorico8]

Description

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?
  • If not, why?:

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 (e.g /game_eggs) 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

[cocorico8]

I'm maybe gonna make a fika headless soon

[redthirten]

I'd like to possibly check this out sometime soon. Are you happy with it's current state after all your changes? Could possibly get it merged after testing. Thanks for contributing 👍

[Zeroradiance]

Tested the Egg and its working pretty well, One thing to note is the lack of access to Fika folders to update versions manually as there is no Variable for the egg to select what version of Fika to install.

If this egg had the above functionality it would be superb.

[coyotte-hue]

Hello, would it be possible to have an egg with the server-csharp version?