Refactor: Consolidates RunOff models with flexible input (#88)

Fixes #87

This change introduces a useInput parameter, allowing users to dynamically switch between reading meteorological data from external files (using CombiTimeTable sources) or providing inputs directly through RealInput connectors. This significantly enhances the model's flexibility and adaptability to various simulation scenarios.

Further improvements include:

    Cleanup and standardization of model parameters and units.
    Synchronization of comprehensive documentation detailing the HBV model structure and implementation.
    Refinement of connector positions and conditional input handling logic.


Co-authored-by: Dietmar Winkler <dietmar.winkler@dwe.no>

Author: dietmarw-se