Adding relations to the schema

[nikgraf]

• Allows to query nested relations
• Validates that a relation type name is part of the the defined entities

API how to include relations in a query:

const events = useQuery({
  types: ['Event'],
  include: {
    attendees: {},
  },
})

API how to include nested relations in a query:

const events = useQuery({
  types: ['Event'],
  include: {
    attendees: {
      badges: {},
    },
  },
})