Refactor CheckValve using quintic Hermite spline interpolation

[AntoineGautier]

We've experienced some NL solver convergence failures that point to the check valve model:
lbl-srg/modelica-buildings#4002
This ticket is to revise the implementation using a similar approach as the pressure-independent actuator models, based on a quintic Hermite spline interpolation (C2) between the closed valve flow function and the fully open valve flow function.
Initial tests with this new formulation show that all convergence issues are eliminated on the models from the above thread (with minor but favorable impact on simulation time).