Remove haproxy

We used haproxy because we had multiple bigcouch nodes but now with a single couchdb node this is not needed anymore. This is needed to debug #8130 further because #8130 might be caused by haproxy irregularities.

(from redmine: created on 2016-05-26, blocks #8130)

Todo

• For nodes where couchdb is on the same server as the webapp/leap-mx, we need to adopt the config to directly use port 5984 to connect to couch @elijah
• Review and merge !70 (merged)