Support Stochastic Model for Instance Start Time in Simulations

[masih]

The current implementation of our simulation uses a synchronised global time to kickstart the next GPFT instance with a configurable EC stabilisation delay. However, this approach may not accurately capture the variability that can occur in real-world scenarios.

In reality, instance start times across participants are likely to be random and unpredictable. To better reflect this, it would be ideal if our simulation allowed configuration of a stochastic model that introduces randomness into the instance start time for each participant.

Acceptance Criteria

1. The simulation should allow configuration of a stochastic model for instance start time.
2. The stochastic model should introduce randomness into the instance start time for each participant.
3. The simulation should be able to generate multiple instances with different start times based on the configured stochastic
   model.
4. The EC stabilisation delay should still be configurable and apply uniformly across all participants.