Rewrite dynamicUI to use special metadata client for getting UI defs.

This includes:

* passing request to almost every call of dynamicUI function (for
  Keystone authentication).

* passing SHA-1 hash of current ui definitions package to Metadata
  Repository

* reducing number of import_all_service() calls in dynamic UI (with
  overhead of querying Metadata Repository they are much more costly
  now).

Change-Id: Ifb0e54940779cc0a83f91f6c8d91447c72b60adf