Merge pull request #2 from OpenMediaVault-Plugin-Developers/master

merge from official master
Fixed cannot input domain in 'DNS search domain' field
Fixed cannot input multiple entries separated with commas
Fixed log entries missing for date from 1 to 9
Restricted 'Common Name' field in certificate tab to alphanum
Fixed iptables rule not added upon boot/reboot
Refined iptables to remove previous rule before adding new rule
Added 'PAM authentication' checkbox
Minor updates following code review
Merge pull request #5 from paul-desvignes/master

PAM authentication feature + several bugfix