Sign up using Codeberg OAuth

[tesseract-two]

It would be great if Modrinth supported signing up via Codeberg similar to the Github and Gitlab authentication.

I'm not a great programmer, but I found this documentation on Forgejo's (software Codeberg runs on) repository: https://codeberg.org/forgejo/docs/src/branch/v1.21/docs/user/oauth2-provider.md