Search: Add search panel

[silvalaura]

We want to add a Panel (like our DropdownContent panel) to Search to support advanced search.

Requirements:

• The contents of the panel will not be prescriptive so it can be customized in each application
• Provide the ability to open and close the panels manually, and handlers for when the panel opens and closes
• Provide a loading state (match Combobox)
• Functionality for focus into and out of the panel
• We should also consider providing styled way for items like ItemsList

[silvalaura]

POC that showcases use case: https://codesandbox.io/p/sandbox/predictive-taxonomy-search-r6n8xp?file=%2Fexample.tsx%3A7%2C19