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/assets/ts/artplayer-tool-iframe.d.ts

@@ -0,0 +1,32 @@
+interface Message {
+  type: string
+  data: any
+  id?: number
+}
+
+declare class ArtplayerToolIframe {
+  constructor(option: { iframe: HTMLIFrameElement, url: string })
+
+  static iframe: boolean
+  static postMessage(message: Message): void
+  static onMessage(event: MessageEvent & { data: Message }): void
+  static inject(): void
+
+  readonly promises: Record<number, { resove: (...args: any[]) => any, reject: (...args: any[]) => any }>
+  readonly injected: boolean
+  readonly destroyed: boolean
+  readonly $iframe: HTMLIFrameElement
+  readonly url: string
+  readonly messageCallback: (...args: any[]) => any
+
+  onMessage(event: MessageEvent & { data: Message }): void
+  postMessage(message: Message): Promise<any>
+  commit<T extends (...args: any[]) => any>(callback: T): Promise<ReturnType<T>>
+  message(callback: (...args: any[]) => any): void
+  destroy(): void
+}
+
+export default ArtplayerToolIframe
+
+export = artplayerToolIframe
+export as namespace artplayerToolIframe;