Adjust Preview Site Create Form Redirect
Issue #3391729 by brianperry, mitchellmarkoff, coby.sher: Associate an oauth consumer with a preview site
Closes #3395392
The preview site edit form is smart enough to redirect back to where the user started but the create form had a hardcoded redirect to decoupled_preview module. This makes some changes so that the redirect can be dynamic. This will also bring the oauth consumer work into the fes-settings branch.