T7935 implemented four basic statuses for event invitees: "Invited", "Attending", "Declined", and "Uninvited". We should brainstorm and come up with others, if there are any other useful statuses that we missed.
Statuses that were no implemented in T7935:
> - isRequired (or similar? For required/optional? But maybe we could just use "Role" for this?)
> - role (or similar? For "Speaker" vs "Bringing Salad".)