NIFI-7573: Add an Azure Active Directory (AAD) User Group Provider

[sjyang18]

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Description of PR

NiFi on Azure Cloud environment may be integrated with AAD and define the group based authorization policies. Combined with OIDC based user authentication, this will improve user/group authorization policy management experience.

Reference:

https://docs.microsoft.com/en-us/graph/api/resources/group?view=graph-rest-1.0

https://docs.microsoft.com/en-us/graph/api/group-list-members?view=graph-rest-1.0&tabs=http

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[sjyang18]

I haver rebased to main and push to see if build failure will be fixed.

[jfrazee]

@sjyang18 Thanks for this, it's going to be really useful. There are three things I think we need to work through:

1. There are a variety of style changes to fix. If we can get this done it'll be easier to work through any additional things.
2. I think we should take a different approach for managing the concurrency/thread safety of the user groups. The most common approach in the rest of the codebase is to use an immutable object with an AtomicReference and use the AtomicReference::set() to effectively swap the values. I created an example in a gist. The idea is that refreshUserGroupData() always creates a new user group object and swaps the values. So the background thread can just call it in a thread safe way.
3. We'll have to add the documentation. There's already bits and pieces in the comments so this should be easy once we work through the rest.

[jfrazee]

@sjyang18 Thanks for the updates! There are a few more suggestions:

1. I think it'd be useful to have the names of the configuration properties in authorizers.xml match the names the user would see in the portal.
2. Since the instructions for configuration/behavior are in the docs I think it can be removed from the comments in the authorizers.xml.
3. The microsoft-graph dependency has been updated several times. As far as I can tell, everything still works with 2.10.0. It might make sense to update the version to that.
4. The microsoft-graph dependency needs to be added to the nifi-azure-nar/src/main/resources/META-INF/LICENSE file. It should say something like "The binary distribution of this product bundles 'Microsoft Graph SDK for Java' which is available under an MIT license." and include the text of the the license.

[jfrazee]

Thanks @sjyang18 everything LGTM.