docs(intro): reorganize and simplify (lvgl#8389)

Co-authored-by: Victor Wheeler <vwheeler63@users.noreply.github.com>
Co-authored-by: Liam Howatt <30486941+liamHowatt@users.noreply.github.com>

Author: 3 people

docs/src/index.rst

@@ -61,8 +61,8 @@ Introduction
     :class:    toctree-1-deep  toctree-landing-page
     :maxdepth: 1
 
-    intro/introduction
-    intro/getting_started
+    intro/introduction/index
+    intro/getting_started/index
 
 
 Details