API

• Add short example for each model in the api/model.md

UV Theory

• EquationOfState.UVTheory:
  • wrong data type for parameters and wrong docstring
  • missing docstring for Perturbation
  • feos.uvtheory.Perturbation: missing docstring
  • feos.uvtheory.UVParameters: "binary saft parameter records"
  • feos.uvtheory.UVRecord: describe attributes and/or default constructor.