For this item to be accepted as complete: - [x] A package must be created under `/interest_points` ; - [x] A node called `collector` must be created inside the package ; - [x] The node must subscribe to `/interest_points/add` ; - [x] The node must subscribe to `/interest_points/update` ; - [x] The node must persist the interest points and modify them as needed ; - [ ] The node must expose a service to get all currently interest points created until now.