repart: add basic support for LUKS2 integrity verification (#39295)

Authenticated disk encryption is experimentally supported by cryptsetup
since v2.0.0 and allows for automatic dm-integrity setup for LUKS
devices. Add support for the mode to systemd-repart. The PR adds support
for `cryptsetup luksFormat --integrity` to systemd-repart and
"encryptedwithintegrity" dissection policy.

Limitations:
- No discard, online-only mode for repart.

Closes #39250