Add rendering section

pre-requisite for multiple PRs and changes I need to make in parallel

index.rst

@@ -97,6 +97,7 @@ The main documentation for the site is organized into the following sections:
    tutorials/i18n/index
    tutorials/gui/index
    tutorials/viewports/index
+   tutorials/rendering/index
    tutorials/shading/index
    tutorials/networking/index
    tutorials/navigation/index

tutorials/rendering/index.rst

@@ -0,0 +1,6 @@
+Rendering
+=========
+
+.. toctree::
+   :maxdepth: 1
+   :name: toc-learn-features-rendering