Feature enhancement for encrypting existing unencrypted pools

Acceptance criteria

• In place conversion from an unencrypted to an encrypted pool.
• In place conversion from an encrypted to an unencrypted pool.
• In place reencryption in case the volume key is leaked.

Dependencies

• This work requires a release including an upstream bug fix in cryptsetup: https://gitlab.com/cryptsetup/cryptsetup/-/merge_requests/589

• This work depends on our upstream PR for the metadata rework: https://github.com/stratis-storage/stratisd/pull/3274