Repository move

[zeuner]

I intend to move this repository to a different Git hoster. I don't want this to become a competition on what is the best centralized Git hoster, as seen in minetest/minetest#12324 . Git was invented as a decentralized version control system, so the most natural way of hosting a repository would also be decentralized or federated. Since there doesn't seem to be such a hoster right now, the best choice seems to be Codeberg, considering that their engine codebase is already being developed with federation in mind, making it probably the Git hoster that will federate first.