feat: add RTL Support and update demo site to Show Arabic/RTL content (#519)

* add LanguageDirection variable

* add .direction-rtl and .direction-ltr clases

* margin -right > margin-inline-end

* keep Codeblocks LTR

* switch to logical properties

* left -> inset-inline-start

* Add Arabic/RTL placeholder text

* Add arabic language

* remove space

* use Html Dir instead of class

* Move codeblock code to layout/article.css and fix 4 spaces codeblocks

* remove unused clases

assets/scss/partials/layout/search.scss

@@ -24,7 +24,7 @@
     label {
         position: absolute;
         top: 15px;
-        left: 20px;
+        inset-inline-start: 20px;
         font-size: 1.4rem;
         color: var(--card-text-color-tertiary);
     }
@@ -51,7 +51,7 @@
 
     button {
         position: absolute;
-        right: 0;
+        inset-inline-end: 0;
         top: 0;
         height: 100%;
         width: var(--button-size);
@@ -78,4 +78,5 @@
             height: 20px;
         }
     }
+
 }