Customize after sign-up path
It would be cool to be able to customize the path a user is redirected after sign-up. Similar to 'After sign out path'.
We need this for https://gitlab.com/gitlab-org/marketing_monthly_release/issues/1#due-march-9-implementation (see last item)
After "sign up" form submitted for gitlab.com, can lead to onboarding page instead of coming back to same signup page.
If we decide to implement this, we will need it for 8.6.
cc @JobV @sytses @DouweM @rspeicher @hanktaylor @AshleyS @nearlythere