VMM/password: generate all crypt() salts w/o trailing $ sign

man5: added misc.dovecot_version to the minimal config example.

VMM/password: moved the 'scheme check' code from pwhash() to the new function verify_scheme(). VMM/Config: use verify_scheme() to check the scheme when LazyConfig.set() is called.

VMM/Config: removed the default value of misc.dovecot_version. There are too many different versions installed on different systems. So, it doesn't make much sense to have a default value.

VMM/Handler: import the errors before raising them. Rephrased the 'permission error' message.

VMM/password: Added support Blowfish/SHA-256/SHA-512 crypt(). Also updated Config and man section 5.

VMM/Handler: code cleanups in the user/alias/relocated info methods.

VMM/Handler: fixed destination check in Handler.aliasAdd().

VMM/Alias: moved the postconf stuff from the Handlers to Alias class.

VMM/{Config,Handler}: moved Config.install() to Handler.cfg_install(). Handler.cfg_install() must be called explicitly. To avoid 'strange' problems.

VMM/cli/Handler: fixed AttributeError in CliHandler.__init__(). Attribute '_scheme' was removed in previous commit.

VMM/Handler: removed password hashing related stuff.

VMM{,/cli}/Handler: adjusted user* methods to the changes in Account. All user methods was renamed from userAction() to user_action(). Added missing docstrings.

VMM/Account: always pass the EmailAddress to the pwhash() call.

VMM/Account: some modifications and small improvements in class Account. - replaced the tid by a Transport instance - check mailbox format dependencies in _repare() - reset all attributes when the Account was deleted - don't select information, we have already, from the db - added __nonzero__() method

VMM/password: added small output check on _dovecotpw().

VMM/common: added a caching dict for version_hex()/version_str()

VMM/Config: Added method Config.install() -> global cfg_dget(). VirtualMailManager.Configuration removed -> some adjustments.

INSTALL: dropped group mail related stuff. UPGRADE: be more details about nobody's primary group.

configuration: Dropped setting misc.gid_mail. That setting was never useful, since none of the virtual users was a member of a system group.

man/{,de/}man5/vmm.cfg.5.rst: Updated descriptions of dovecotpw and password_scheme settings.

VMM: added new modules password and pycompat.hashlib. INSTALL: updated

VMM/maillocation: Use the hex version, since we are able to convert it to an string, in case of a failure.

VMM/{Account,common,Handler}: Improved version_hex(). - common: version_hex() now supports 'serials' > 16. Added version_str() as counterpart to version_hex(). - Account, Handler: updated hardcoded Dovecot versions.