Make solum-api serve up the API

Update the solum-api command to serve up the solum REST API.

Part of blueprint api

Change-Id: I6c95438b66bb48407a4b6bd39fb1c91cd780ae7c
Add devstack integration

Add devstack integration for solum.  Devstack has a plugin mechanism for
unofficial projects to integrate with it without having to change any
of devstack itself.  This commit includes the files and some
instructions on how to use them.

Change-Id: I4d6c52d76cb2658d5626be74b3e2980205de083d
Merge "Make solum-api serve up the API"
Merge "Add devstack integration"