Move styles related to content to typography*.less

This will make it easier to share styles with mobile apps. See further
patches.

In the process remove tag selectors, which are too specific, from
ul.gallery subrules.

See https://trello.com/b/BW5L3PEn/mobile-app-sprint-31-main-article-browse-search
for further information on motivation.

Change-Id: I7547340664a3f4e52d217ca10acc68891a8f7f41
Merge "Move styles related to content to typography*.less"