Refactor parameter class (mainly interpolation)

requested review from @a.wellmann

added 7 commits

• 248b0068 - Rename variables in GridScalingKernelManager, too
• e1eb5ca6 - Rename parameters in UpdateGrid to fit the new naming
• c9f666a1 - Rename variables accordingly in indexRearrangement
• d031f915 - Rename in InterpolationCellGrouper as well
• 41e48e4d - Rename in kernel interfaces
• b76b5bf2 - Rename offset in main scaling kernel
• a6615463 - Miscellaneous renames

Compare with previous version

removed review request for @a.wellmann

approved this merge request

merged

mentioned in commit d96ca783