Sarah's work to remove slug and owner from new organizations form and refactor view tests

https://aptivate.kanbantool.com/boards/5986-econsensus#tasks-1549115, https://aptivate.kanbantool.com/boards/5986-econsensus#tasks-1081183, 
https://aptivate.kanbantool.com/boards/5986-econsensus#tasks-1388793

Also now:
- link to add new org is now an Add link next to title on Your Organizations page (used to be a sentence at bottom of screen
- new test runner means we no longer have to import all tests in tests/__init__.py
- new Decision only gets is_active org members as watchers, not just all org members.