docs: Various refinements ahead of launch

This is a series of changes across the documentation to improve the
overall first-user experience. Key changes:

  1. New "Express setup" section in the "Getting Started" page.
  2. Rename and reorder the left-hand menu bar components
  3. Fix various copyright dates
  4. Add presubmit animated gif to the pw_presubmit docs

Change-Id: I22a75ace8c2be15a6e5890d6e1b3618a1d53eefa
diff --git a/docs/style_guide.rst b/docs/style_guide.rst
index 285ded8..f69f2a3 100644
--- a/docs/style_guide.rst
+++ b/docs/style_guide.rst
@@ -208,7 +208,7 @@
 
 .. code-block:: cpp
 
-  // Copyright 2019 The Pigweed Authors
+  // Copyright 2020 The Pigweed Authors
   //
   // Licensed under the Apache License, Version 2.0 (the "License"); you may not
   // use this file except in compliance with the License. You may obtain a copy of