cleanout testswarm from the manifests

testswarm has been phased out a while ago. This cleanout the contint
manifest but keep the 'testswarm' system user which is moved to the new
'testswarm' module.

The module is very simple but will be amended later on to actually
install the new testswarm system.

Change-Id: I4f4d4df62fdfa6fc5f3aa0ee9d9287e7a9281e08
Merge "cleanout testswarm from the manifests" into production