Implement Ramer-Douglas-Peucker line simplification

It would be nice to have an op for the [Ramer-Douglas-Peucker algorithm](https://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm) to decimate/downsample a signal/polyline, as [suggested on the forum](https://forum.image.sc/t/need-to-find-the-angle-at-the-corner-of-the-skeleton/20184/6?u=imagejan) by `eljonco`.

Start by reading the linked Ramer-Douglas-Peucker algorithm description and the forum discussion, then inspect imagej-ops for existing operations that process signals or polylines. Done means adding an operation that decimates or downsamples a signal or polyline using this algorithm, with behavior aligned to the requested use case.

Written by the indexing model from the issue text.