UI Skinning

- Added skinning UI in the admin UI
- Implemented sections and subsections
- Allow specification of colors through color picker
- Allow specification of urls
- Reverting to original value
- Converted full version of latest version of skin file to LESS template
- Removed old skins and documented their values
- Created static skin files for when app servers are down
- Don't show OAE UI as configurable module
- Include error pages in global admin server nginx config
- Made UI use new skin endpoint
- Made UI skin endpoint cached in the nginx config
- Fix anonymous top nav display issue

Note 1: This PR depends on the skinning Hilary PR
Note 2: This PR is based on the notification PR, which should be merged before this one