WIP Heptapod PAAS Runner: service aliases

Changing the image name also changes the resulting default alias to
something like `foss.heptapod.net__heptapod__dependency_proxy__containers__redis`
so we need to add an explicit alias in this case.

--HG--
branch : heptapod
1 job for topic/heptapod/dependency-proxy-docker in 1 minute and 57 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed test-python #248075

00:01:57