Create the Calendar page

[EasySouls]

Create the UI and UX for the Calendar page located in app/(app)/calendar.tsx

For now, the backend endpoints are not done for the events, but you can use placeholder data.
The easiest way to get started is to create an Event interface in types/index.tsx, and use that in the components.

You can use third-party packages to display the calendar. It should also support creating new events and submitting them and also editing existing ones. Depending on the state of the development of the authentication, but you can also enable Head of Departments to edit all events belonging to their department, allow anything for admins, and restrict basic civil guards' access to only their own events.

When the endpoints are created later, please use useQuery instead of the fetch api.