Add clipboard methods to js engine.

assets/init.js

@@ -1357,4 +1357,30 @@ let APP = {
             method: 'getPlatform'
         })
     }
+}
+
+/**
+ * Set clipboard text
+ * @param text {string}
+ * @returns {Promise<void>}
+ * 
+ * @since 1.3.4
+ */
+function setClipboard(text) {
+    return sendMessage({
+        method: 'setClipboard',
+        text: text
+    })
+}
+
+/**
+ * Get clipboard text
+ * @returns {Promise<string>}
+ * 
+ * @since 1.3.4
+ */
+function getClipboard() {
+    return sendMessage({
+        method: 'getClipboard'
+    })
 }