Fix margins in uploads dashboard

This reduces the margin and font-size for the number of uploads message
(consulted with Munaf).

Also, adds margin at the bottom of the page (after last image's
description) and prevents the upload message from jumping from one place
to another when JS is loaded.

Change-Id: Ibcb8b571204ab9e1651957ff0e286d67f743b95d
Merge "Fix margins in uploads dashboard"