Improved Org/Activity creation workflow

A single button, hey, like “Add Activity”, that says “oops you’re not logged in, so log in or create a new account.  And once you’ve finished that it says “hey, you need to create an Org to create activities.  And when you’ve done that, it’s clear how to make your first activity.  Never left puzzling “where am I now? What am I to do?”

---DEV NOTES---

Updated this so that if you only have one org it redirects you straight to add an activity to that org, if you have two it takes you to my-organizations, and if you have none it takes you to 'create and organization'.  I would like to make changes to offer help text along the way to help this flow even smoother.