VMM/handler: Reworked methods _get_disk_usage, _delete_home and
_delete_domain_dir. Deleted method _isdir.
Config
   cfs - configset sect.opt val
   cfg - configget sect.opt
   ds - domainservices: smtp pop imap sieve???
subcommand for displaying support crypt algorithms.
- Aliases
    - avoid looping aliases
- Domain
    - optional limits for number of:
        + accounts
        + aliases
        + destinations/alias
        + alias domains
Database:
   public.users.digestmd5: add "character varying(48)"
	Outlook will love it. (`doveadm pw -s DIGEST-MD5.hex -p 1 -u 0`)