Added show extra_specs for flavors, code for default flavor to load from...

... config file, code to boot instance using port speed and unit tests for all and servers

Change-Id: I951c6be5ed8604a958b4f4413ceac6415f1520fd
This loading should be done inside of `jumpgate/compute/drivers/sl/__init__.py` and the flavor details (or a class wrapping access to the flavors) should be passed in explicitly to each route that needs it. That way, all loading is done at the beginning of the application and dependencies are more explicit, which leads to easier testing. An example of this exists for the endpoint listing for the sl identity driver.