zfs: run load-key on mount/unmount

[Mic92]

No description provided.

[Lassulus]

do we also need to do this for zfs_volume?

[Enzime]

[web01] + zpool list zroot
[web01] + zpool import -l -R /mnt zroot
[web01] Key load error: Failed to open key material file: No such file or directory
[web01] 0 / 1 keys successfully loaded

This PR didn't work for me, however I'm not sure if it's because I already have an installed system and I was just trying to run the mount script

I tested again, this is working 🎉 I think I just forgot to copy over the ZFS key before trying the mount script