Add URL admin

[ecumike]

Create URL admin page, as typical, where you can:

• Add a new URL
• Edit a URL
• De-activate a URL
• Whatever else makes sense related to URL model.

[rcalfredson]

Do you think that ability to edit the filters would fall into this role? This question comes up in light of the fact that the filter UI is getting ready to go live, and I am thinking about the way we would want to configure any filters on the current production instance.