GraphQL: Missing group's organizer name / organizer id

[schloerke]

Related: #118
GraphQL Group: https://www.meetup.com/api/schema/#Group

find_groups() returned organizer_id and organizer_name.

This data is no longer directly provided by the GraphQL API. There is an Event host (which points to a User) object, but this can change from event to event.

I do not easily see a way to determine who is the point of contact for a group.

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Result: Would remove organizer_id, organizer_name from find_groups().
cc @ledell