Migrate packages to guru

[ethannij]

I wanted to put a package https://github.com/ethannij/ethannij-overlay/tree/main/x11-drivers/OpenTabletDriver-bin into guru, but since dotnet is a dependency and isn't available in ::guru or ::gentoo I cant submit it. After talking a bit about it in the guru irc, I figure that it might be beneficial for you and guru to migrate the packages over to ::guru. More people would be able to add packages that take advantage of dotnet, and dotnet would get more attention and support.