Short Description

Implement a state that connects to the backend that is able to fetch members(participants) of the current room.
Connect the selection for the school with the list of schools-endpoint in the backend. Notice: During implementation roomParticipants were renamed to roomMembers

Links to Ticket and related Pull-Requests

[x] QA: In addition to review, the code has been manually tested (if manual testing is possible)
[x] PO: Any deviation from requirements was agreed with Product-Owner / ticket author / support-team
[x] DEV: Every new component is implemented having accessibility in mind (e.g. aria-label, role property)

Notice: Please keep this Pull-Request as a Draft (or add WIP label), until it is ready to be reviewed