Rucio server: pin all dependencies

[rdimaio]

As part of the work related to this request #6663, where we want to relax version constraints for the Rucio client (to make it possible to use it as a library), we should also tighten the version constraints for the server, fully pinning all dependencies. Related to this issue too: #6750

For Dependabot: it might be better to allow non-security updates for development dependencies, in order to not fall behind.