Allow user to specify which columns to display in Web UI collection view

Currently, when viewing documents in the Web Interface under Collections > Content tab, the display shows default columns like _key and a generic content field. Data is not easily discoverable and hard to process as a human.

Feature Request: Add the ability to select which specific document attributes should be displayed as columns in the collection content view, perhaps even add inline filter/sort options per column. This would allow for a table-like view of the columns that the user has specified he/she wants to see.

The collection view would then be much closer to other database browsers' user interfaces with which users are already familiar (most likely). It would improve usability when working with documents that have many attributes, allowing users to focus on relevant fields without needing to write AQL queries for simple data browsing.