add Gtnh

[Alfredoes234]

Description

Adding Greg Tech New Horizons capability using the java 17_21 version.

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

[parkervcp]

I am only considering this because the minecraft eggs are in their own repo now and not flooding a single repo with egg merge requests.

[Alfredoes234]

Did I do something wrong? Or do you mean that now it is separated you can now add more stuff?

[parkervcp]

Now that the minecraft eggs are separate from the rest I am willing to accept more. I turned down them down previously because a lot were covered by what we already had.

More and more are changing to other services so I see there being a need for more specific ones.