Allow file editing within Site Edit modal

[lprivette]

• [x] Add inline buttons/functions for edit/view/delete:
• [x] Clicking the 'View Details' button opens the file data in an expansion panel: https://material.angular.io/components/table/examples
• [x] When the expansion panel is open the 'View Details' button text changes to 'Close Details'
• [x] Clicking 'Edit' opens the expansions panel with editable fields
• [x] When Editing a file, the save button is at the bottom.
• [x] If a user has made changes to the file but does not save it and then tries to exist the modal or hit the main save then warn them.
• [x] Clicking 'Delete' deletes the file