Docs redesign (#728)

* Adding a dark mode
* Adding reference for types to summary pages
* Adding API Reference
* Adding modifiers to methods/fields/etc
* Minimizing files input
* Caching a lot of the output pages
* Cache only for each execution
* Adding API references to existing docs

docs/input/analyzer/rules/_layout.cshtml

@@ -1,7 +1,7 @@
 @inherits StatiqRazorPage<IDocument>
 
 @{
-    Layout = @"/_layout.cshtml";
+    Layout = @"../../_layout.cshtml";
 }