Feature/email trigger changes

This pull request fixes for email design content as well as changes to triggers (rules).

b/17281770
b/17203372 (already fixed)
Code like this is really really hard to maintain. It also makes it almost impossible for @pkanazir to make improvements. Using python's format function instead of string concatenation would be a step in the right direction, separating html into templates is what's actually needed here.

There probably isn't enough time to do the necessary changes in time for this sprint, but please have this comment in mind when making future updates.