refactor(html): split UI define modules and narrow slider imports (#659)

packages/html/src/define/ui/time-separator.ts

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