File thumbnails/icons - feature request

[benhaynes]

From directus created by psuplat : directus/directus#2207

I have few tables that contain link to a single file within their structure. That link not necessarily has to be an image, it could be a pdf or some other type of document.

Currently when a file is selected of type other then image, the table content preview shows broken image icon, like so:

It is more of an aesthetics issue, rather then functionality, but it would be nice if directus detected the file type, and if it was an image show the thumbnail, but for anything else one of the following: icon representing document type, just the file extension(.pdf, .doc, .xyz) or full file name (although this might not be such a great idea if user upload files with long names).