Major win in nested routes & links
** Properly nested the activities resousrce in the workouts resource; able to CRUD activities
** Fixed links to reflect new nested routes sitewide
** Changed form partial names from 'form' to 'new_form'
** Updated controller actions for activities
** More conditional logic to better address null states - could probably be refactored still
** Created except to the nested routing - allowing for activities#index to exist as /activities if no workoutid present