Build with libcryptsetup-dev in dlopen mode to enable dm-verity

Re-enable dm-verity support. Use the new dlopen configure flag, so that instead of linking against libcryptsetup.so, it is loaded dynamically at runtime, and only if the verity feature options (-o verity...) are used, to avoid the dependency on the libcryptsetup package being pulled in unconditionally. Add it as a Suggests on cryptsetup-bin.

Closes: #951048