Define the authentication model

[matvelloso]

We need to build AAD authentication into this. The application has to be multi tenant capable so any Azure subscription can log in. In addition, the application still has to work in anonymous mode if all we want is to share a diagram with others.

In order to make the authentication work we will also need a database for storing this multi tenancy data. Eventually we might need to partition this database but I wouldn't worry for this here.

[rsarieddine]

You want to keep a record of all users and have roles associated to them? we can create an Azure database for that. inserts records on first sign up