feat(render): Renderer with LOD selection, 3.3 and 4.3+ upload paths, headless smoke test

CMakeLists.txt

@@ -19,6 +19,7 @@ add_library(plot_core
   src/render/buffer.cpp
   src/render/vertex_array.cpp
   src/render/program.cpp
+  src/render/renderer.cpp
   src/plot/ticks.cpp
   src/plot/axis.cpp
   src/plot/grid.cpp