[VA to PF] Add Virtual Assistant body

The following PF components should be moved to the new extension:

• Card
• CardHeader with optional actions (currently fullscreen and  minimize, but I don't think we should add these directly to the Extension)
• CardTitle (configurable)
• CardBody
• CardFooter (with additional components)

How it should look (without body contents)

Working mock: https://github.com/patternfly/virtual-assistant/pull/3

The code is here:

Body code: https://github.com/RedHatInsights/astro-virtual-assistant-frontend/blob/main/src/Components/AstroChat/AstroChat.tsx

Skeleton: https://github.com/RedHatInsights/astro-virtual-assistant-frontend/blob/main/src/Components/AstroChat/AstroChatSkeleton.tsx

Scss: https://github.com/RedHatInsights/astro-virtual-assistant-frontend/blob/main/src/SharedComponents/AstroVirtualAssistant/astro-virtual-assistant.scss