build Xamarin apps on buildserver

We have several RFPs for Xamarin apps:

rfp#5
rfp#114
rfp#79 (closed)

So I am opening this issue in order to centralize the discussion about installing Xamarin on the build server.

These app are originally meant to be built with Microsoft Visual Studio. However, we can also use the mono-xbuild Debian package to build from the CLI. But we would still need the Xamarin.Android framework.

I opened a Debian RFP for this: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=900406

Edit: We might also be able to use this repository to build Xamarin from source.

Edited Mar 03, 2021 by Hans-Christoph Steiner