build: Fix indexing so it works on HTML and PDF.

- Remove all genindex.rst files, these are generated and should not
  exist in our source.
- Fix the HTML templates so the local specialisation works.
- Add a index link to the sidebar for HTML.

Note, there is no TOC entry for the index in the PDF output and I
cannot figure out how to add one.

Closes #3503

1 files changed, 9 insertions, 2 deletions

diff --git a/common/_templates/layout.html b/common/_templates/layout.html
index 7f64789..7a66d8a 100644
--- a/common/_templates/layout.html
+++ b/common/_templates/layout.html
@@ -1,5 +1,12 @@
 {# Import the theme's layout. #}
 {% extends "!layout.html" %}
-
+{% block sidebartitle %}
+    <a href="https://docs.rtems.org/">RTEMS Documentation Project</a>
+    {{ super() }}
+{% endblock %}
+{% block menu %}
+  {{ super() }}
+  <a class="reference internal" href="genindex.html">Index</a>
+{% endblock %}
 {# Custom CSS overrides #}
-{% set bootswatch_css_custom = ['_static/my-styles.css'] %}
+{% set css_files = ['_static/my-styles.css'] %}