Implement 911 model responder logic

[jardiamj]

The logic of the responder in the NG911 models is missing. This requires issue #490 to be solved, and would include the following processes:

• Responder travel time
• Responder response time
• Dispatch queue
• Units availability

[jardiamj]

I am facing the issue of modeling the responders' travel time and response time. Specifically, I need to figure out what kind of probability distributions are good fits and then do parameter fitting; for which data is needed.

This is a good research paper on travel time distribution: Analyzing travel time distribution based on different travel time reliability patterns using probe vehicle data

I have not found papers about the time a responder spends on the scene. We could analyze the data provided by Seattle PD which provides the start of incident and end of incident time. However, I believe this might include the responder's travel time and it is only police related. One would imagine that EMS and Fire incident response data are different.

Seattle PD Incident data