Add universal analytics snippet
Make universal analytics snippet always on

This is for testing.
Remove cookie domain
Only use cross domain analytics on IER transactions

This is intentionally scoped to IER in a simple fashion as we decided not to build
a generalised solution until we have more than 1 example of user needs for this
kind of tracing, eg, do we have to support non-GA solutions, non-universal analytics?

Keep it simple for now.

https://www.pivotaltracker.com/n/projects/1008986/stories/74213668
Tweaked GA linking params, as per the guide from Pete on IER
Test that we only include analytics JS on regsiter to vote