When switching identities, the managesieve plugin still connected to
the default sieve server. Hook into managesieve_connect to redirect
the sieve connection to the remote account's server.
Adds sieve_host, sieve_port and sieve_auth columns to the database,
a Sieve section to the identity settings form, preconfig support for
sieve_host, and localized labels for all 7 languages.
- fr_FR, de_DE: add missing keys (imap.delimiter, smtp.auth.imap,
smtp.auth.none)
- it_IT, nl_NL: rewrite with current key names (form.common.*,
form.imap.*, form.smtp.*) and add all missing SMTP keys
- All 7 languages now have the same complete set of keys
