Several fixes and refactorings to the interpolation methods

Fixes #388 (closed), unfortunately the implementation of interpolateNANs with limit is not None is quite a bit slower, then the incorrect previous one. Any ideas to speed things up are highly appreciated, I couldn't find a better solution despite a few hours of trying.

CHANGELOG.md

@@ -18,6 +18,7 @@ SPDX-License-Identifier: GPL-3.0-or-later
 - Changed Default value of the parameter `limit` for `SaQC.interpolateIndex` and `SaQC.interpolateInvalid` to ``None`
 ### Removed
 ### Fixed
+- Interpolation/resampling routines with `limit` > 2
 
 ## [2.2.1](https://git.ufz.de/rdm-software/saqc/-/tags/v2.2.1) - 2022-10-29
 [List of commits](https://git.ufz.de/rdm-software/saqc/-/compare/v2.2.0...v2.2.1)