Implement the root and v1 entry points of the API

An resource is returned at the root URL of the API and contains
information about the API itself as well as links to the specific versions
of the API. Also, a resource is returned at the root URL of each specific
version of the API and contains information about the resources available
on that version, links to documentation and available content-types that
are supported.

Implements blueprint implement-root-api-action

Change-Id: I20905febd4e0a39f5499fce1d54f5bb159b50b2d