Register a test Firefighter Identity with security role 'Firefighter' [hardware steel-thread]

As a Prometeo tester, I need a way to register a default firefighter Identity, so that I can sign in as a Firefighter when testing the mobile app.

This is not about actually signing-in (which is story #99). It's about the configuration necessary to support sign-in for initial testing.

3 sub-tasks:

* Create a Firefighter Test Identity for signing into the mobile application. There's no Prometeo functionality here - just creating an account with IBM ID (or Google ID, MS ID, ...)
* Register that Identity with the Prometeo deployment, so that it allows that user, and only that user, to sign in as a firefighter. (Can hard-code this identity for now, it will be superseded by 'add/remove users' functionality later on)
* Assign the Prometeo user a security role. If the role is 'Firefighter User' they can sign in to the mobile app. If it's anything else, they can't.

Also note that the system should support a single account being registered as both a Firefighter and an Admin. This is because we can't expect Admin users to register two separate user accounts with the IDaaS service if they also happen to be a firefighter.

See story #95 for similar configuration on the Command Center side.