EEVEE-Next world volume are infinite like Cycles. EEVEE-Classic world volumes
end at the clip_end of the camera/viewport. This can lead to confusion as
it would render different then expected.
This PR adds an operator to convert a world volume into a mesh volume. The
operator can be found in the shader editor (world mode) and in the properties
panel/World/Volume.
**Why an operator?**
As this alters the content of the scene we want the artist to be in control of
the conversion. Doing it automatic lead to a lot of complexity and cases that
might not be expected by the user.
Pull Request: https://projects.blender.org/blender/blender/pulls/119734
f01e84e3a5