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/blog/_nextprevious.cshtml

@@ -1,6 +1,4 @@
-
 @inherits StatiqRazorPage<IDocument>
-@model IDocument
 
 @{
     var older = Model.GetDocument(Keys.Next);

docs/input/blog/_posts.cshtml

@@ -1,5 +1,5 @@
 @inherits StatiqRazorPage<IEnumerable<IDocument>>
-@foreach (var post in Model)
+@foreach (var post in Model ?? Array.Empty<IDocument>())
 {
     <div>
         <h3 class="mb-0"><a href="@Context.GetLink(post)">@post.GetString("Title")</a></h3>
@@ -19,7 +19,7 @@
             @if (category != null) {
                 var categoryUrl = @Context.GetLink($"blog/{NormalizedPath.OptimizeFileName(category)}/index.html");
                 <span>
-                    to <a class="text-blue-800 underline" href="@categoryUrl">
+                    to <a href="@categoryUrl">
                         @category
                     </a>
                 </span>

docs/input/blog/posts/_layout.cshtml

@@ -20,7 +20,7 @@
     }
     @if (category != null) {
         <span>
-            to <a class="text-blue-800 underline" href="@Context.GetLink($"blog/{NormalizedPath.OptimizeFileName(@category)}/index.html")">
+            to <a href="@Context.GetLink($"blog/{NormalizedPath.OptimizeFileName(@category)}/index.html")">
                 @category
             </a>
         </span>