Class Instance and Event Manager for JS

Currently we have a lot of the following happening:

1. Double/triple etc... instantiation of classes
2. Double/triple etc... registration of events.

This happens when you use turbolinks because the page changes but the javascript never gets dump. A simple boring solution to this would be to make a central location for all instances and events. On page:change we dump the necessary js instances and events.

Config settings will allow you to keep/dump events and instances through a page change.

This issue is of high importance because we currently have this happening and causing problems in our codebase.

I imagine that the script itself does not need to be big.

cc @alfredo1 @annabeldunstone @iamphill @elvongray @dzaporozhets @rspeicher