Build containers for riscv64

[bedroge]

No description provided.

[bedroge]

The workflow that we use for the architectures, doesn't work for riscv64 (yet):

• the Debian and CentOS images that we use are not available for riscv64, Debian only has an experimental/unstable one and for CentOS there's nothing at all, see here;
• on an Ubuntu 20.04 image, building the package does not work, due to missing dependencies (e.g. Valgrind) on riscv64

As suggested by @amadio on Slack, we could switch to another workflow where we just build the client itself from source (instead of building packages), see:
https://gitweb.gentoo.org/repo/gentoo.git/tree/net-fs/cvmfs/cvmfs-2.9.2.ebuild#n70
That requires some more changes, though, and an initial attempt failed due to issues with protobuf on riscv64, so this needs some more work too.

[boegel]

@bedroge There's a riscv64 container image now for Ubuntu 22.10, cfr. https://hub.docker.com/r/riscv64/ubuntu/tags

[bedroge]

@bedroge There's a riscv64 container image now for Ubuntu 22.10, cfr. https://hub.docker.com/r/riscv64/ubuntu/tags

That was already there when I tried this, but from what I remember, I had similar issues as with 20.04.

[trz42]

Looks good (and most familiar). I left a comment regarding the inclusion of eessi-upload-to-staging in the container. Feel free to ignore that if you think it's unproblematic.

[trz42]

Great. Looks promising to build some software.