Add a minimal client for pipeline2

Should probably be moved to a separate project one on these days.
Major simplification of the pipeline2 interface

Just return the result of data.xml/parse-str and let the clients figure
out what part of that xml is of interest to them instead of mapping it
into yet another map of maps.
Make room for more functionality in the pipeline2 ns
Implement all job related functions
Remove unnecessary requires
The body returned by delete is empty

so just return whether the status was successful