Generating region maps from OpenEXR depth data

[curiousjp]

Thanks for your hard work on this add-on - it has proven quite useful! As an addon for a script I have written to quantise OpenEXR depthmaps for use in controlnet, I have now added a feature to render out region maps for use with your masking system by tagging specific spans of depth as belonging to specific regions. It seems to work well so far and I thought you might find it interesting, although I may make some further tweaks to it in the future.