feat: improve forgeStageTwoQuery to allow select/omit for singular model populate

[DominusKelvin]

Resolves balderdashy/sails#4667

I also account for the normal behaviour of Waterline projections not allowing both select and omit

Now this sort of subcriteria will be treated as valid subcriteria for populating associations

 const tickets = await Ticket.find({
      where: { event: event.id, status: { '!=': 'cancelled' } },
      sort: 'ticketHolderEmail DESC',
      select: ['ticketHolderEmail', 'status', 'publicId']
    })
      .populate('ticketType', { select: ['name'] })
      .populate('order')

[luislobo]

Good improvement! It would be good to have unit tests