Sign-in to the Command Center web app [software steel-thread]

**"As a Command Center leader, I need authentication security that lets me sign into the Command Center Web and keeps out unauthorised users".**

Can only sign in if:
* User has an account with the IDaaS service
* User is registered with Prometeo
* User role in Prometeo is 'Command Center User'
Anything else and Prometeo should give an 'access denied' error.

Note - for this steel thread epic, the goal is minimal - one user can sign in. This is just to enable any IDaaS integration issues to be discovered as early as possible. More sign-in and security related functionality will come in subsequent epics.

See story #99 for similar configuration on the mobile app side.

Questions:
* What IDaaS service will Prometeo use - IBM, Google, MS, ...?