Implement `skeletonize()`

[opatiny]

Implement a function that skeletonizes a mask. https://homepages.inf.ed.ac.uk/rbf/HIPR2/skeleton.htm

Is there anything similar in image-js already?

Ref to Matlab equivalent function: https://nl.mathworks.com/help/images/ref/bwskel.html

[lpatiny]

This method will only apply on a binary image (mask) and return a new mask.

const skeleton = mask.skeletonize();

Need to check what is the best algorithm and this could be useful:

• Publication

Here are some example of application

• http://devdoc.net/python/scikit-image-doc-0.13.1/auto_examples/edges/plot_skeleton.html
• https://tirthajyoti.github.io/Scikit-image-book/Skeletonize.html
• https://imagej.net/plugins/analyze-skeleton/