enhance: Add comprehensive .gitignore for deb-mock project

- Add mock-specific build artifacts (chroot/, mock-*, mockroot/)
- Include package build files (*.deb, *.changes, *.buildinfo)
- Add development tools (.coverage, .pytest_cache, .tox)
- Include system files (.DS_Store, Thumbs.db, ._*)
- Add temporary and backup files (*.tmp, *.bak, *.backup)
- Include local configuration overrides (config.local.yaml, .env.local)
- Add test artifacts and documentation builds
- Comprehensive coverage for Python build system project

This ensures build artifacts, chroot environments, and development
tools are properly ignored in version control.

docs/_includes/head-custom-google-analytics.html

@@ -0,0 +1,10 @@
+{% if site.google_analytics %}
+  <script>
+    (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
+    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
+            m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
+        })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
+    ga('create', '{{ site.google_analytics }}', 'auto');
+    ga('send', 'pageview');
+  </script>
+{% endif %}

docs/_includes/head-custom.html

@@ -0,0 +1,9 @@
+<!-- start custom head snippets, customize with your own _includes/head-custom.html file -->
+
+<!-- Setup Google Analytics -->
+{% include head-custom-google-analytics.html %}
+
+<!-- You can set your favicon here -->
+<!-- link rel="shortcut icon" type="image/x-icon" href="{{ '/favicon.ico' | relative_url }}" -->
+
+<!-- end custom head snippets -->