Add a bunch of point cloud algorithms

[DelazJ]

Fixes #8122, fixes #8150, fixes #8164, fixes #8167, fixes #8233, fixes #8248
Picking and recombining screenshots at https://www.lutraconsulting.co.uk/blog/2023/05/30/pointcloud-qgis-processing/ per suggestion by @saberraz
This PR needs both #8436 and #8456. So thanks to any reviewers... (and I have inline comments/questions and parameters description unfilled)

[DelazJ]

@alexbruy can you help fill in some description? And I also have some inline questions. Thanks

[DelazJ]

@alexbruy gentle ping

[github-actions]

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[github-actions]

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