feat: introduce ArtplayerToolIframe for iframe control

- Removed the old ArtplayerPluginIframe implementation.
- Added ArtplayerToolIframe class with methods for iframe communication.
- Implemented postMessage and onMessage methods for message handling.
- Created a new TypeScript definition file for ArtplayerToolIframe.
- Updated documentation links to point to the new iframe tool.
- Added npm ignore file and README for the new package.
- Included compiled and uncompiled versions of the new iframe tool.
- Updated package.json with relevant metadata and exports.

docs/index.html

@@ -98,10 +98,6 @@
                             <a
                                 href="/?libs=./uncompiled/artplayer-plugin-ads/index.js&example=ads">artplayer-plugin-ads</a>
                         </li>
-                        <li>
-                            <a
-                                href="/?libs=./uncompiled/artplayer-plugin-iframe/index.js&example=iframe">artplayer-plugin-iframe</a>
-                        </li>
                         <li>
                             <a
                                 href="/?libs=https://cdnjs.cloudflare.com/ajax/libs/hls.js/1.5.17/hls.min.js%0A./uncompiled/artplayer-plugin-hls-control/index.js&example=hls.control">artplayer-plugin-hls-control</a>
@@ -174,6 +170,10 @@
                             <a
                                 href="/?libs=./uncompiled/artplayer-tool-thumbnail/index.js&example=tool.thumbnail">artplayer-tool-thumbnail</a>
                         </li>
+                        <li>
+                            <a
+                                href="/?libs=./uncompiled/artplayer-tool-iframe/index.js&example=iframe">artplayer-tool-iframe</a>
+                        </li>
                     </ul>
                 </div>
             </div>