Accordion component

[danielagattoni]

👷‍♀️ Work in progress 👷‍♀️

Dev tasks:

• Some of the keyboard nav implementation is in src/Menu/Menu.tsx to reference
• a11y good practices at https://www.w3.org/TR/wai-aria-practices/#accordion
• reuse built-in fannypack components if possible e.g. https://fannypack.style/utils/hidden may also be useful.