systemd-cryptsetup dependency chain

[mikn]

Description of changes:
This introduces a chain of dependencies for enabling systemd-cryptsetup. Initially, I did not compile the cryptsetup binary itself and I did not package the systemd-cryptenroll binary as we would embed them in our admin container and in our bootstrap system, but I guess it would be more useful to have them part of the primary system? Willing to discuss though.

I am also unsure whether the devmapper-event library is needed or not.

Testing done:
I have made sure the binaries don't give linking errors when invoked, but I have not tested primary functionality yet. Will happen later.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[mikn]

I am currently maintaining this in our variant repository as well, but would appreciate to get this upstream as discussed.

[cbgbt]

Thanks for your contribution, and apologies for the latency -- things are a bit slow on account of the holidays. We'll have a look!