DDF-669 DDF-670 DDF-682

DDF-670 - Restyles the admin application modules.  Setup initial application selection page for Jeren and Sam's work.

DDF-669 - Created Feature management backend API and Feature UI via
config plugin.

DDF-682 Created configuration plugin API framework.  Adjusted
configuration UI to work within a Configuration Plugin.
I would agree it would be cleaning to just use the view from /configurations/.  Though for this code to work we would need to have the configuration module started to provide the JS.  I will remove the copied code and we can address the code sharing in a separate ticket.