Feature/ab#2217 configurable roles

[ztarbug]

App now supports arbitrary external role names, that are mapped to standard internal role names.

Description

Application needs users to have one of three roles admin, user, reader. External names can now mapped via application.properties.

Motivation and Context

Standard role names are very generic and hard to use in multi application scenarios. Thus this PR presents a mapping mechanism.

How has this been tested?

Local Keycloak with sample users.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[witchpou]

Please examine this warning: Mockito is currently self-attaching to enable the inline-mock-maker. This will no longer work in future releases of the JDK. Please add Mockito as an agent to your build as described in Mockito's documentation: https://javadoc.io/doc/org.mockito/mockito-core/latest/org.mockito/org/mockito/Mockito.html#0.3