Allow running unattended, with qvm-backup-restore --passphrase-file.
This require few modifications:
- copy the passphrase file into the DisposableVM (that VM knows the
passphrase anyway, so there is no extra data leak)
- close the terminal when operation finishes
Closing the terminal would eliminate almost all the feedback (operation
log, errors, warnings etc), so write it into a file in DisposableVM and
later extract it and show on the stdout. Similar to qvm-run, color it
red as a content coming from a VM.
QubesOS/qubes-issues#5310
Due to strangeness of KeyError (it overrrides str method) in some
cases exceptions received superflous quotation marks when inheriting
from it.
fixesQubesOS/qubes-issues#5106
