Add a script to create Azure Active Directory App Role Assignments

[pim-simons]

Is your feature request related to a problem? Please describe.
We have several customers where we use a Powershell script to assign Azure AD App Roles to another service principal. For example this is very useful when you have an Azure API Management instance and use the validate-jwt step to validate if certain roles have been assigned and allow/deny access based on that. This script allows for creating the Role on the 'main' Application Registration and assigns it on another service principal.

Describe the solution you'd like
Create script to:

• Get a list of available roles and to which service principles they are assigned
• Add a role assignment to a service principle and create the role if it does not yet exist
• Remove a role assignment from a service principle