feat(v11): Popover

* Breaking changes *

- The `Popover` now uses a different markup. The trigger becomes a child of the component.
- The new `PopoverContent` becomes an additional child of the `Popover` component.
- remove `relative` property

tests/Popover.test.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { Popover } from "../types";
+  import { Popover, PopoverContent } from "../types";
 
   let open = false;
 </script>
@@ -9,12 +9,10 @@
   closeOnOutsideClick
   align="right"
   caret
-  relative
-  light
   highContrast
   on:click:outside="{() => {
     console.log('on:click:outside');
   }}"
 >
-  <div style="padding: var(--bx-spacing-05)">Content</div>
+  <PopoverContent style="padding: var(--bx-spacing-05)">Content</PopoverContent>
 </Popover>