[Dovecot] Add new imapsync + dependencies

[Dovecot] Syslog-ng: Do not trim after each push to Redis
[Dovecot] Add new cronjob to trim all Redis logs every minute (will be moved in the future)

data/Dockerfiles/dovecot/trim_logs.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+redis-cli -h redis LTRIM ACME_LOG 0 LOG_LINES
+redis-cli -h redis LTRIM POSTFIX_MAILLOG 0 LOG_LINES
+redis-cli -h redis LTRIM DOVECOT_MAILLOG 0 LOG_LINES
+redis-cli -h redis LTRIM SOGO_LOG 0 LOG_LINES
+redis-cli -h redis LTRIM NETFILTER_LOG 0 LOG_LINES