CIDEVSTC-49 - Refactors Parameter-based DM service methods to respect IonObjects

- Adds new service method to dataset management: `create_parameter`
- Changes the interface of `create_parameter_function`

The efforts are made to provide the user interface and services with the ability to create parameters and parameter functions using IonObjects in lieu of coverage-model dictionaries. The methods use the same parsing and handling logic that's available in ion_loader.py. The goal is to consolidate as much of the behavior between them into the service and still use the cacheing and state available in ion_loader for preload only.