Home: Add menu item for new top-level landing page

It will be indexing the main docs entrypoints.

This page is special, should not necessarily be part of the content
tree, that's why it is flagged as orphaned.

The aim is to slot this page into the URL namespace as a landing page
for all the documentation based on Sphinx, straight at
https://cratedb.com/docs/.

CHANGES.rst

@@ -6,6 +6,7 @@ CHANGES
 Unreleased
 ----------
 - CSS: Adjusted inner alignment being off for cards with links
+- Home: Added new top-level landing page, indexing the main docs entrypoints
 
 2024/06/27 0.33.0
 -----------------

src/crate/theme/rtd/crate/sidebartoc.html

@@ -9,6 +9,13 @@
 
   {% else %}
 
+  <!-- Home. -->
+  {% if project == 'CrateDB: Guide' and pagename == 'home/index' %}
+    <li class="navleft-item current"><a class="current-active" href="/docs/guide/home/">Docs Home</a></li>
+  {% else %}
+    <li class="navleft-item"><a href="/docs/guide/home/">Docs Home</a></li>
+  {% endif %}
+
   <!-- Section A. -->
   {% if project == 'CrateDB Cloud' %}
     <li class="current">
@@ -19,7 +26,7 @@
     <li class="navleft-item"><a href="/docs/cloud/">CrateDB Cloud</a></li>
   {% endif %}
 
-  {% if project == 'CrateDB: Guide' %}
+  {% if project == 'CrateDB: Guide' and pagename != 'home/index' %}
     <li class="current">
       <a class="current-active" href="{{ pathto(master_doc) }}">Guides and Tutorials</a>
       {{ toctree(maxdepth=3|toint, collapse=True, includehidden=theme_globaltoc_includehidden|tobool) }}