refactor: delete base64js

instead of base64 library you can use built-in JS functions `btoa()` and `atob()`

web/assets/js/util/utils.js

@@ -478,4 +478,21 @@ class Wireguard {
             privateKey: secretKey.length > 0 ? secretKey : this.keyToBase64(privateKey)
         };
     }
+}
+
+class Base64 {
+    static encode(content = "", safe = false) {
+        if (safe) {
+            return window.btoa(content)
+                .replace(/\+/g, '-')
+                .replace(/=/g, '')
+                .replace(/\//g, '_')
+        }
+
+        return window.btoa(content)
+    }
+
+    static decode(content = "") {
+        return window.atob(content)
+    }
 }