Add general-purpose query filters to REST API

The current Glance implementation is somewhat simplistic, especially for a multi-tenanted environment. This specification is for a proposal to enhance the Glance REST API by allowing query parameters on the /images and /images/detail resources.

In a multi-tenanted environment, especially one with thousands of users or customers, returning a collection of images can be extremely cumbersome. By providing filtering via query string parameters, this collection can be used to reduce the set of images to a more manageable size.