Add an edit tag dialog

[dv297]

As a member of the Graffiti Abatement Tracking Program
I want a dialog where I can edit existing tags
so that I can easily add and remove details from an existing tag.

We know when we are done when

• the user selects a tag from the tag list and an edit button is available
• when the edit button is clicked, it brings you to a dialog where the existing information is filled in
• on the edit dialog, there is a submit button that allows you to save the new information

[JakeLaCombe]

You can find the corresponding mockups attached. Note that the inputs fill follow that same structure throughout the entire application.