chore: 删除不再使用的 TypeScript 声明文件，并添加新的插件声明文件

docs/assets/ts/artplayer-plugin-vast.d.ts

@@ -0,0 +1,20 @@
+import type Artplayer from 'artplayer';
+
+export = artplayerPluginVast;
+export as namespace artplayerPluginVast;
+
+type Option = (params: {
+    art: Artplayer;
+    id: string;
+    ima: any;
+    imaPlayer: any;
+    $container: HTMLDivElement;
+    playUrl: (url: string) => void;
+    playRes: (res: string) => void;
+}) => void;
+
+type Result = {
+    name: 'artplayerPluginVast';
+};
+
+declare const artplayerPluginVast: (option: Option) => (art: Artplayer) => Result;