clean up util folder

[yxlao]

• Remove unused scripts
• Remove docker (outdated, not maintained)
• Standardize naming

The only remaining files are as follows:

Open3D/util
├── check_cpp_style.cmake
├── check_style.py
├── install_deps_macos.sh
├── install_deps_ubuntu.sh
├── make_documentation.sh
└── run_ci.sh

---

This change is 

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[griegler]

Reviewed 57 of 59 files at r1, 2 of 2 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @benjaminum)

[pwais]

@yxlao The online documentation still references headless docker support: http://www.open3d.org/docs/release/tutorial/docker/docker-gui.html Did the feature never work? Dockerized headless CPU rendering is incredibly useful.

[yxlao]

@pwais dockerized headless CPU rendering should be feasible. Our documentation build runs headless rendering https://github.com/intel-isl/Open3D/blob/master/.github/workflows/documentation.yml. It's possible to cook your own Dockerfile by following the scripts in documentation.yml.

[pwais]

@yxlao yup I saw the CI stuff 👍 but I'd rather not have to try to cook up my own Dockerfile when there appears to be one that works (tho it got removed :( ) in this commit... Is the functionality referenced in the current online docs going to be restored, or are the docs out of date and going to be deleted?

Lastly, I'm not sure if you're familiar with this part of Open3D, but is there any way to configure Open3d do render-to-image without using Xvfb/mesa? I.e. is there any way to get Open3D to use "CPU-only functionality" to do rendering (sort of like putting pytorch or tensorflow into CPU mode)? If not, no big deal, but I wanted to ask given that it would be another way to do "headless" or CPU-only rendering. Also, this appears to be an Intel project, so I was hoping there might have been some feature here. I've looked through many of the examples and haven't found anything though.

oh huh, is the python package open3d on pypi right now actually built with headless rendering support?
https://github.com/intel-isl/Open3D/blob/8a7a77c10d4f0339fb5c52b913235f6e5a23b937/cpp/pybind/_build_config.py.in#L10

i may be confused between open3d "headless rendering" mode and the Xvfb software rasterizer. when Open3d is build with headless rendering, can it use both the GPU and the CPU (via Xvfb) ?

I've tried some of the jupyter examples and so far I got things to work in a docker container (based on lambda-stack ubuntu focal) https://github.com/lambdal/lambda-stack-dockerfiles/blob/master/Dockerfile.focal but that's via exposing host X11 into the container. I haven't gotten Xvfb + jupyter inside the container to work with the pypi release of Open3d; not sure if it's supposed to.