Draft: Interpolation

To do:

• Create helper classes for various interpolators (regular grid, sphere bivariate, constant) to make code more modular and easier to maintain
• Handle cases where longitude spans meridian
• Remove deprecated z argument
• Check if longitude correction is still needed for sphere bivariate interpolation
• Generalize GeospatialInterpolator to also handle depth interpolation (remove DepthInterpolator)
• Method for returning grid nodes
• Improved logging
• Make sure docstring are updated and accurate
• ...

Related issue: https://git-dev.cs.dal.ca/meridian/kadlu/-/issues/9