Add Feature: Multiple instances per Subject

[peersky]

Current MAODistribution only creates a factory that distributes Subjects.

There are few boundary cases, particularly:

• If exactly same subject is created (We should not allow that)
• If User wants to create a separate instance within a subject itself they must have ability to
  • It can register instances to play the subject following principal game cost & time parameters #64
  • it can unregister instances from playing a subject
  • It emits events for instance listing/delisting