- move CI only prerequisites to github actions
- Add linux, mac prereq actions
- Add an action for indicating dependency versions
- Move ninja installation into its own script
- Re-enable renderdiff test.
- Cache the mesa directory so that we're not spending time pulling
and compiling it.
- Move python prereqs into the script and use venv.
The public dep for mesa has moved on to beyond llvm-18, but the
version we're compiling against is not supported by this change.
We workaround by ensuring that the llvm dep is less than 18 but
consistent with the clang version.
We use Mesa's gallium swrast to render as the driver with
Filament's backend set to GL. We provide a few scripts to parse
the tests (as jsons) and run gltf_viewer to produce the rendering.
