adjusting HTTP connection to make sure feedback will be sent to host with ssl on and off, close #11739
changing FEEDBACK_URL variable in settings
refactoring SendFeedback class and adding HTTP_USER_AGENT

to the feedback sent from omeroweb
making QA port configurable
removing whitespace (@sbesson request)
Merge pull request #1816 from aleksandra-tarkowska/11739_qa_host

#11739 qa host