Re-enable OSMesa builds and add EGL build variant

[basnijholt]

Checklist

• [x] Used a personal fork of the feedstock to propose changes
• [x] Bumped the build number (if the version is unchanged)
• [x] Reset the build number to 0 (if the version changed)
• [x] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [x] Ensured the license file is being packaged.

This closes the issue https://github.com/conda-forge/vtk-feedstock/issues/223, and superseded https://github.com/conda-forge/vtk-feedstock/pull/153 and https://github.com/conda-forge/vtk-feedstock/pull/224.

I have locally built the

• EGL variant on Linux for Python 3.9, 3.10
• OSMesa variant on Linux for Python 3.9, 3.10
• qt variant on Linux for Python 3.9, 3.10

We're not using the external version of GLEW for EGL/OSMesa, because GLEW needs to be compiled with EGL/OSMesa.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[basnijholt]

@msarahan, @ccordoba12, @grlee77, @jasonb5, or @matthiasdiener, could you please merge/review this? 😄

All CI builds are passing (with the exception of one of the Windows build timing out for unrelated reasons.)

[basnijholt]

@matthiasdiener, thanks!

Do we need to wait for more reviews before merging?

I am kind of blocked by not having this, so my apologies for being impatient 😄

[basnijholt]

@conda-forge-admin, please restart ci

Just such that all CI builds will have a green checkmark. All builds do already work!

[matthiasdiener]

@matthiasdiener, thanks!

Do we need to wait for more reviews before merging?

I don't know. I was wondering/hoping that someone else from @conda-forge/vtk could also take a look.

[matthiasdiener]

By the way, would you like to add yourself as a maintainer @basnijholt ?

[basnijholt]

@matthiasdiener, sure! I have just done that.

[matthiasdiener]

@conda-forge-admin rerender

[basnijholt]

Everything is passing! ☑ :tada:

[grlee77]

Okay, let's try it out. Thanks, @basnijholt!