Support aad_apps for AZDO service endpoints

[brk3]

PR Checklist

• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• My code follows the code style of this project.
• I ran lint checks locally prior to submission.
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Description

For reasons that are not entirely clear to me yet, CAF Terraform
has two ways of creating service principals:

aad_apps {
  # uses ./modules/azuread/applications
}

or,

azuread_applications {
  # uses ./modules/azuread/applications_v1
}

Also for reasons not yet clear to me, this repo provides two lzs for
configuring AZDO: caf_solution/add-ons/azure_devops and
caf_solution/add-ons/azure_devops_v1

The azure_devops module appears to use aad_apps, while azure_devops_v1
uses azuread_applications. This commit updates azure_devops_v1 to
support both forms of AD config.

Does this introduce a breaking change

• YES
• NO

Testing

[arnaudlh]

hey @brk3 to clarify a bit on your doubts, azure_devops_v1 is the newest way to create AZDO objects. we kept to old azure_devops for backward compatibility but definitely will use v1 going forward as it allows much more granular way to create AZDO resources!

--> It's actually a good feedback and I will add a note in the ``azure_devops``` directory :)

Same applies for azuread_applications vs aad_apps

[arnaudlh]

LGTM