GUI-58: Snapshots Landing Page Redux

Implemented auto-refresh if any of the snapshots are in progress when the page is loaded or when any of the snapshots fetched during the auto-refresh are in progress.

Also implemented the ability to delete a snapshot or go to the detail page from the tile/table view "gear icon" drop-down buttons.

Removed the left column filters since it was only showing the "status" filter, which will almost always be "completed" unless there are items in progress.  Buys us additional real estate for the landing page, especially for the table view.  Will discuss the proposed UX change with @JMoLo