Generalise PointingInterpolator for calibration parameters

[ctoennis]

Please describe the use case that requires this feature.
For the use cases DPPS-UC-120-2.21 (calculating and calibrating pedestals), DPPS-UC-120-2.22 (calculating and calibrating gain), and DPPS-UC-120-2.28 (Pointing corrections) calibration parameters will be generated that will need some form of interpolation similar to the basic pointing information (linear interpolation for the pointing correction and a sort of step function-like interpolation for gain and pedestals).

Describe the solution you'd like
I would like to modify the PointingInterpolator into a more general interpolator class that is told which data to interpolate and which interpolation method is to be used.

Describe alternatives you've considered
Alternatively we can have a new interpolator class for the pedestals and gain as they need a different method of interpolation and simply just modify the PointingInterpolator to also handle pointing corrections.

Additional context
Link to pull request:
Pull request
Links to the use cases:
Pedestals
gain
Pointing