feat(core): add poster component (#457)

packages/html/src/define/ui/poster.ts

@@ -0,0 +1,9 @@
+import { PosterElement } from '../../ui/poster/poster-element';
+
+customElements.define(PosterElement.tagName, PosterElement);
+
+declare global {
+  interface HTMLElementTagNameMap {
+    [PosterElement.tagName]: PosterElement;
+  }
+}