Implemented text direction switch

Update index.php, text-direction-switch.js, and text_alignment.php

htdocs/js/text-direction-switch.js

@@ -0,0 +1,16 @@
+const eTextDirectionSwitches = document.querySelectorAll(".text-direction-switch");
+const eTextDirectionTargets = document.querySelectorAll(".text-direction-target");
+
+document.addEventListener("DOMContentLoaded", () => {
+    eTextDirectionSwitches.forEach(eSwitch => {
+        eSwitch.onclick = function() {
+            eTextDirectionTargets.forEach(eTarget => {
+                if(eTarget.style.direction === "rtl") {
+                    eTarget.style.direction = 'ltr';
+                } else {
+                    eTarget.style.direction = 'rtl';
+                }
+            });
+        };
+    });
+});