Change the default imap idle timeout of 29 minutes to 60 seconds

This will fix the mail_room hanging issue. Since most IMAP servers are not keeping connections open for 29 minutes. And even when a mailserver support that a firewall in between can stop the connection after X amount of minutes anyway.

mentioned in issue gitlab-com/infrastructure#89 (closed)

mentioned in commit ba39e420

This has been merged and picked to 8-9-stable branches.

mentioned in commit 03684d16

mentioned in commit 13f621a3

I assume this means this will be in 8.9.2 but not in 8.9.1.

8.9.1 was already released.