Introduce basic Pecan/WSME framework for KDS

So far there is simply a CLI application called kds-api that launches
the server using the reference wsgi server and a test just to
make sure things are wired in correctly.

blueprint: key-distribution-server
Change-Id: I17f1943eb6cd71f6059606a1a099f5761896b131
Merge "Introduce basic Pecan/WSME framework for KDS"