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/_ViewStart.cshtml

@@ -1,3 +1,3 @@
 @{
-    Layout = @"/_layout.cshtml";
+    Layout = @"_layout.cshtml";
 }