[dovecot] Configuration file format changes

[Timo Sirainen]

After tomorrow's 0.99.8 release I think it's time for a new config file
format. It could be made backwards compatibile with the old format, but 
there would be new tree-like categories. I was thinking something like
this:

# global settings
protocols = imap

# "foo.server.org" is just descriptive name
# settings inside server { .. } will override global ones.
# groups (namespace, login settings, auth settings) aren't replaced
# unless same name is used.
server foo.server.org {
  imap_listen = 1.2.3.4
  ssl_cert_file = /etc/ssl/certs/foo.cer

  # default namespace (no name)
  namespace {
    type = private
    mail = mbox:~/mail
  }

  # Have to quote so '#' won't be thought out as comment.
  # I think quoting should work everywhere actually..
  namespace "#maildir" {
    type = private
    inbox = yes # this namespace contains INBOX
    mail = Maildir:~/Maildir
  }

  # override global auth default
  auth default {
    auth_mechanisms = plain digest-md5
    auth_realms = foo.server.org
    auth_userdb = ldap /etc/dovecot-ldap.conf
    auth_passdb = ldap /etc/dovecot-ldap.conf
  }
}

server bar.server.org {
  imap_listen = 1.2.3.5
  ssl_cert_file = /etc/ssl/certs/bar.cer

  namespace {
    type = private
    #mail = #autodetect
  }

  # shared mailboxes between users
  # eg. user/timo.sirainen/some-shared-folder
  namespace user {
    type = user
    mail = /home/%u/mail/shared
  }
}

server baz.server.org {
  imap_listen = 1.2.3.6
  ssl_disable = yes

  # Only Courier-like INBOX namespace
  namespace INBOX {
    type = private
  }
}

# common namespace between all instances
namespace shared {
  type = shared
  mail = mbox:/var/lists:INDEX=~/mail/.shared/
}

auth default {
  auth_mechanisms = plain
  auth_userdb = passwd
  auth_passdb = pam
}