Use Icinga 2's default Livestatus socket path as default when configuring a livestatus resource
Do not use a default regular expression for stripping off parts of a username when configuring an auto-login backend

There's no safe default for this.
Merge branch 'master' into feature/packages-4075
Use 'icingaweb2' as default application prefix for logging to syslog
Use '/var/log/icingaweb2/icingaweb2.log' as default path when logging to file
setup: Use 'icingaweb2' as default authentication backend name