Simulate sensor data via APIs - to support manual and automated CC dashboard testing [software steel-thread]

**"As a Tester or Developer, I need to be able to simulate 'live' sensor data from Firefighter IOT devices, so that I can test the Command Center (CC) Web Application."**

This simulation mechanism will be used for lots of things :
* Developers ad-hoc testing their CC Dashboard enhancements / defect fixes / etc
* Testers validating software changes (e.g. change to a graph or an alert)
* End-of-sprint playbacks to the stakeholder team (simulate a few mins of sensor data & show how the CC Dashboard looks)
* Recording promo videos

In this 'steel-thread' epic, It doesn't necessarily have to be fully-automated - this is just about getting a minimal simulation running to test integration of API / messaging / database / dashboard / etc. However, later on (story #105) , everyone will need to be able to use it, so keep in mind it'll need to be easy enough for a variety of people on the team to use when testing and/or demoing.

Documentation on how to run simulations should go in the github repo for Open Source Contributors (inc us!) to use, same as for story #97