Make get_all_server_info and get_scaling_group_servers use pure-http

The metrics.py code had to be updated to deal with this, and I refactored the effectiness a little bit into metrics.py, so that there's a new get_all_metrics_effects function extracted from get_all_metrics.

I've added unit tests for get_all_metrics_effects, and left the unit tests for get_all_metrics in place (and updated them to ensure that code is using pure-HTTP properly). The tests for that are pretty nasty, but hopefully they'll go away if more of metrics.py gets Effect-ified.


If you don't mind, I would prefer leaving it here with a comment saying "it is broken and needs to work with effect" instead of removing it. I am pretty sure no one (including me) will remember and look for it in history. If/when the time comes, I would end up writing it again.