[SOGo] Update SOGo to 5.5.0 + syslog Version Update (in Config)

This PR is updating SOGo to the new 5.5.0 Release (https://github.com/inverse-inc/sogo/releases/tag/SOGo-5.5.0) <-- Available in master.

It also includes the nsyslog Update to 3.28 (since the new SOGo builds are using a newer version), which fix a warning message inside the sogo container that the nsyslog version is outdated and can be upgraded to 3.28

This new release will have the Docker Image Tag: mailcow/sogo:1.106