ghcup-metadata: Various fixes from 9.10.1
Use Debian 12/x86-64, Debian 10/aarch64, and Debian 11/aarch64 bindists where possible.
Due to a large amount of spam we do not allow new users to create repositories, they are "external" users. If you are a new user and want to create a repository, for example for forking GHC, open a new issue on ghc/ghc using the "get-verified" issue template
Use Debian 12/x86-64, Debian 10/aarch64, and Debian 11/aarch64 bindists where possible.