Forgejo

[mcmikemn]

I decided to add Forgejo for a few reasons:

1. I wanted to see how similar it was to gitea (it's almost identical).
2. If I decide to use Forgejo instead of gitea, I wanted to migrate my gitea repos to forgejo because it's supposed to be very easy to do now (it is) but forgejo seems likely to become increasingly different from gitea in the future and the process might become more complex or I might have to recreate my repos from scratch.
3. To test of adding instances for gitea.

I tested multiple instances simultaneously running on a server: both run and I can SSH to both, but I haven't tested oauth2. Assuming Oauth2 also works with instances, we could added instances to gitea pretty easily.