feat(packages): add poster component to video skins (#994)

packages/html/src/define/video/skin.ts

@@ -14,6 +14,7 @@ import '../ui/pip-button';
 import '../ui/play-button';
 import '../ui/playback-rate-button';
 import '../ui/popover';
+import '../ui/poster';
 import '../ui/seek-button';
 import '../ui/time';
 import '../ui/time-slider';
@@ -28,6 +29,10 @@ function getTemplateHTML() {
     <media-container class="media-default-skin media-default-skin--video">
       <slot name="media"></slot>
 
+      <media-poster>
+        <slot name="poster"></slot>
+      </media-poster>
+
       <media-buffering-indicator class="media-buffering-indicator">
         <div class="media-surface">
           ${renderIcon('spinner', { class: 'media-icon' })}