[Places] Add indication of operating status to the Places schema

[jensgoossens-tomtom]

We want to support indication of closed places. As an initial outcome, we want to start by adding an operating status indication to the Places schema, with possible values open, closed and temporarily_closed.

For full context please also see RFD 37: How do we want to handle "closed" places? and Add an operating status field to the Places data

Proposal would be to add a field in the 'properties': 'operating_status' with enumeration values of 'closed', 'open' or 'temporarily_closed'

Looking for feedback on whether we should make this property required from the get-go or not?
Making it nullable means we can roll out the schema change already without any code changes, but might lead to confusion for our users.