Remove opencast Maven repo from pom.xml
Remove opencast Maven repo from pom.xml

It stopped working, but its artifacts are cached in JTalks, so they
will still be downloaded from there.

mihnayan/jcommune,vps2/jcommune,Noctrunal/jcommune,vps2/jcommune,vps2/jcommune,mihnayan/jcommune,NCNecros/jcommune,oatkachenko/jcommune,jtalks-org/jcommune,NCNecros/jcommune,Z00M/jcommune,CocoJumbo/jcommune,oatkachenko/jcommune,CocoJumbo/jcommune,Z00M/jcommune,NCNecros/jcommune,CocoJumbo/jcommune,Noctrunal/jcommune,Z00M/jcommune,Noctrunal/jcommune,jtalks-org/jcommune,oatkachenko/jcommune,mihnayan/jcommune,jtalks-org/jcommune