Configure Dovecot’s autocomplete plugin.

Adds/subscribes Drafts, Sent, Junk, Trash and Archive mailboxes.
Merge branch 'master' of https://github.com/al3x/sovereign
Merge branch 'master' of https://github.com/al3x/sovereign
Enable Roundcube's managesieve plugin or server-side filters

These are the changes necessary to enable Roundcube's manage sieve plugin to mange server-side sieve filters.

Signed-off-by: PajamaSoft <support@pajamasoft.com>
Merge pull request #101 from PajamaSoft/roundcube_managesieve

Roundcube managesieve plugin and automatic folder creation