32-bit support

[mzihlmann]

I think there is some interest in a 32-bit version for raspbian based home-lab clusters. I see no limitation that would block us from delivering a 32-bit version. There is some bit-fiddling done with mode-bits iirc, but I rather see this as an opportunity to clean it up. To verify functionality it should be enough to just run all integration tests with a 32-bit binary on the same 64-bit platform, I don't think there is a dire need for continuous testing afterwards.