Create a planet decorator for the rendered Planet object

## Description
I want the planet objects to manage their own states including their orbits. The objects are Three.js defined objects that we would want to wrap around in a decorator and give it more responsibilities. Additionally we would want to keep the domain as anemic as possible.

## Acceptance Criteria

- Decorator exists for planet with updating behaviour.

## Implementation

- Create a class that contains the three.js object of the planet
- Add an Update method to that class