Expand mumble pwhash field to allow for passlib 1.7.3+

passlib 1.7.4 now adds eight more characters to a password string to define its version and type

https://passlib.readthedocs.io/en/stable/lib/passlib.hash.bcrypt_sha256.html#format

The existing model wasnt long enough, though it had some leeway and tests updated

If running a seperate mumble server, it will need to kept in sync with the AA server version for compatability support.