Remove "application.base.url" configuration key

When OpenMeetings server is connected to both a local network (http://server.local:5080/openmeetings) and Internet (http://server.domain.com:5080/openmeetings), java screen sharing application use always "application.base.url" configuration key as server address.
So it's impossible to use screen sharing from both access types.
I suggest using HTTP_REFERER dinamically for retrieving current application url, especially when it's used behind a reverse proxy.