passlib is unmaintained and has not had a release since 2020
a recent bcrypt release just broke passlib
see https://github.com/pyca/bcrypt/issues/684
trove's use of passlib is pretty tirval so this change
just removes it as a depency and delegate the random password
generation in trove.common.utils to the generate_random_key
function in the trove.common.crypto_utils module
Change-Id: I6b6c64147c627025d5f89db6032d1c54445df94f
3367c25e77