WIP:  apache for loadbalancing

This is a quick POC / WIP to demo using apache instead of haproxy for loadbalancing our APIs.

I think this gives us more flexibiltiy as we can enable in the APIs role itself ( in this case in keystone ) rather than a big monolithic haproxy.conf.      We also already have apache running for horizon, so it could reduce number of services.    apache also has better logging options that haproxy which can only log to syslog. 
Looks like copypasta. a2dissite_binary in the enable_site function.