ui/calendar: move query to calendar component

[Forfold]

Describe the Bug: Now that we have a global suspense fallback, when Next/Back is selected on the calendar, the whole page reloads.

If we move the query to the calendar component and wrap that with <Suspense> inside the <Card>, this would be avoided.

[mastercactapus]

Would this be a case where a spinner makes sense?

Ideally, we'd spin the page until the initial load, and then spin over the calendar (but not the next/back buttons) while we load new data.

[Forfold]

I think we could still pull off the delayed loading with a linear progress at the top of the calendar card, but yeah contained loading within this component is necessary