Since the Channel manager overview is created through a REST (http) call, we should be able remove the channelmanagerhostgroup from hst:hosts and remove the defaultport from hostgroup

I've set this improvement to TOP because it makes configuration much better!

Namely, currently, depending on the ENVIRONMENT (dev, test, acct, prod) we need to modify the hst:hosts/@hst:channelmanagerhostgroup value.

We can instead check the referer header from the request now in the channel manager overview, to find the correct hst:virtualhostgroup : Namely, the hst:virtualhostgroup contains the hst:cmslocation : Thus, the hostgroup to show in the channel manager is the one that has the cmslocation equal to the referer (except for a trailing slash most likely)

The same holds for the hst:defaultport on the hostgroup : This can just be the port of the 'referer' header.