Renaming model and adds 

This pull request covers three changes:
- Renames model `InterventionPointDeployments`  to `InterventionPointInteraction` and propogates the change
- Adds a backend check to prevent deletion of an experiment if the experiment has any intervention points installed in Canvas via `canvas.py` method `experiment_has_installed_intervention`
- Models.py change to enforce Experiment and Intervention Point name uniqueness in database