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.
Can also use OSGi constants: 
```java
Constants.SERVICE_PID
```
http://www.osgi.org/javadoc/r4v42/org/osgi/framework/Constants.html#SERVICE_PID