azuread_service_principal: support the features block

[manicminer]

This adds a features block to the service principal resource and data source. Service principals are configured by Azure using magic tags. The presence of a tag value enables a particular feature or behaviour, and the absence disables or removes that feature.

These magic tag values are not officially documented and have been deduced via the portal and some community resources (see below).

Because we already allow tags to be set manually, this features block is an alternative to specifying tags. The same can be achieved with either, the latter is just more frustrating to users who don't wish to trawl the web for these magic values.

These are translated into schema properties as follows:

Schema Property	Magic Tag	Default Value
custom_single_sign_on_app	WindowsAzureActiveDirectoryCustomSingleSignOnApplication	false
enterprise_application	WindowsAzureActiveDirectoryIntegratedApp	false
gallery_application	WindowsAzureActiveDirectoryGalleryApplicationNonPrimaryV1	false
visible_to_users	HideApp	true

Sources:

• https://docs.microsoft.com/en-us/powershell/module/azuread/new-azureadserviceprincipal?view=azureadps-2.0
• https://docs.microsoft.com/en-us/answers/questions/24259/identify-saml-enabled-apps-in-azure-ad.html
• https://docs.microsoft.com/en-us/answers/questions/312760/export-application-list-from-enterprise-applicatio.html
• https://docs.microsoft.com/en-us/answers/questions/322804/getting-more-info-on-azure-ad-applications.html
• https://docs.microsoft.com/en-us/answers/questions/79677/listing-all-enterprise-applications-configured-for.html
• https://www.microsoftpressstore.com/articles/article.aspx?p=2473127
• https://newbedev.com/azure-active-directory-what-is-the-difference-between-a-service-principal-and-an-enterprise-application
• https://nedinthecloud.com/2019/07/16/demystifying-azure-ad-service-principals/
• https://nedinthecloud.com/2020/01/19/enabling-conditional-access-for-azure-active-directory-applications/
• https://nmw.zendesk.com/hc/en-us/articles/1500008027822-Advanced-Install-Creating-AzureAD-application-for-NME
• https://www.mikestephenson.me/2021/01/23/setup-azure-ad-app-for-conditional-access-in-a-custom-app/
• https://adatum.no/azure/azure-ad-application-using-powershell
• https://dailysysadmin.com/KB/Article/4041/list-all-of-your-enterprise-azure-ad-authenticated-applications-with-saml-using-powershell/

Closes: #354
Related: #7 and #173

[stephybun]

LGTM 👍🏼

[manicminer]

Test results

[github-actions]

This functionality has been released in v2.3.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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