Balance event page by moving elements on the right side.

In an effort to balance the event page, I moved a few elements like the toolbox and the similar events list on the right side. The left side is too long and will become longer when this bug is resolved [0]. @johngian @wraybowling @dailycavalier thoughts?

If this something that we want to proceed with, I will open a bug in order to document the effort.

[0] https://bugzilla.mozilla.org/show_bug.cgi?id=1106071