[Client] Create dropdown component

[nicholas-codecov]

We need to create a composable dropdown component that will have a handful of different features included in it:

• Display a summary message
• Open when a given query param is passed in the URL
• Render a child when opened
• Is sticky to the top of the page for when large file lists are present

May be worth looking at Radix to see if there are any useful foundational components that can be used.

Designs can be found here.