protoproxy - update usage examples to current

update the usage examples to the current situation
with eqiad and esams vs. pmtpa. clean remnants
and at the same time show how it to use it with
multiple backends and proxy server names.

Change-Id: I9d1c4fc279b587a50ecc3dcaff3bce29b175fd8b
Merge "protoproxy - update usage examples to current" into production