VMM/Handler: Implemented Handler._chk_other_address_types().
Removed the static methods accountExists(), aliasExists(), relocatedExists()
and _exists().
Config
   cfs - configset sect.opt val
   cfg - configget sect.opt
   ds - domainservices: smtp pop imap sieve???
- Aliases
    - avoid looping aliases
- Domain
    - optional limits for number of:
        + accounts
        + aliases
        + destinations/alias
        + alias domains