Adjusted timeouts on haproxy

• IMAP should have a maximum connection timeout of 30min according to IMAP IDLE, and cyrus closes the connection after 32min, so we use that plus a 30s margin. Closing connections earlier can lead to imap processes that wait for a client that never comes back (until timeout).
• Mysql connections are reused in swoole, and shouldn't be closed too quickly, otherwise we get a lot of warnings in mariadb.
• LDAP connections may be long running.