DDF-804 - Adding the new SourcesPlugin for the catalog sources tab.

* Fix Sources UI so it uses new templates and shows in the catalog tabs.
* Sources can be added and edited
* Clicking the source row will open the edit dialog
* Dynamic add/edit form generation
* Added new template for checkbox style options
* Added LESS to the catalog project
* Added the + and refresh buttons back to the sources view page.
* Added client-side check to prevent adding two source configurations with the same name.
* Source name is now editable and updates all existing configurations.
* Added checks to ensure that newly chosen name does not conflict with existing names
Should use the app version specified in the catalog parent pom (ddf.admin.app.version) instead of hardcoding it in here. If you need the newer version (1.1.0-SNAPSHOT) you'll want to update that variable.