Venue panel: several venues, invited staff and the customer's own address

One account can now run several venues from a Venues screen with a real switcher and a New venue button. Staff receive an invitation instead of a password someone typed for them, and a person's role belongs to one venue and carries down to the places below it. A venue customer's staff sign in at the customer's own subdomain, which has no sign-up and no sales pitch, and the panel opens on an overview: this month's allowance, questions by outcome, open faults and the most-asked and not-found questions.