Make simulations modular

Make simulations generatable with JSON or YAML files. I.e., the JSON/YAML file will specify what static objects to have(i.e., what shape), with what dimensions, in what location, with what coeff. of static and dynamic friction; and also specify the shape, dimensions, mass, coeff. of static and dynamic friction of any dynamic objects. When the scene loads, it should first read the JSON/YAML file and generate the scene.

When working on this, you are also responsible for creating a schema in JSON/YAML. You must also carry out JSON/YAML Schema validation when loading any JSON/YAML file as a level.