remote x86 hydra builder: Add Yubikey provisioning

[mkaapu]

• Environment for Yubikey provisioning (legacy Hydra builds)
• Add Yubikey signer accounts for build3 and build4

[mkaapu]

Provides environment for provisioning Yubikey as described here:
https://github.com/tiiuae/scs-pki-research/tree/main/yubikey

As Hydra is legacy system, this is not full automation of signing server with Nix, just providing environment where signing server can be set.

Tested on build4 Ficolo machine.

[tervis-unikie]

Incorrect subject capitalization.
Take githooks into use and check github actions for warnings when making a PR.

[mkaapu]

Incorrect subject capitalization. Take githooks into use and check github actions for warnings when making a PR.

Thanks @tervis-unikie for reminding. I rebased with main, installed git hooks and fixed commit subject.
However, commit message checking seems to fail for some other reason:

Error: Failed to retrieve commits (https://api.github.com/repos/tiiuae/ghaf-infra/pulls/80/commits)
Error: API rate limit exceeded for 20.172.5.33. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)
Error: Process completed with exit code 7.

[mkaapu]

OK. I just re-run commit message check. It was just probably some internal GitHub error. Maybe too many checks running parallel, no idea really..
But check passed with re-run.