Add one-time key support on flash drive

[nazar-pc]

I'd like to use this instead of pamusb-common, but the latter also has one-time key support.
Essentially, when flash drive is connected and serial number is correct, its partition is mounted and contents of the special file is checked. Unlocking only happens if contents of that file is correct and immediately after that file contents is updated and partition is unmounted.

Would be really nice if you can add such support with something like udisksctl.