Add api_management_gateway_hostname_configuration

[dvob]

Add support for hostConfigurations in API management gateways.
For this I took more or less the api_management_gateway resource and data source as a template and adjusted it accordingly.
Unfortunately I can't run the integration tests because I don't have a client_id and client_secret to access an Azure tenant.

[katbyte]

Thanks @dvob - overall this looks good but we need to fix up the tests:

[manicminer]

Removed the resource as it was already added in #17962 with slightly different name, and renamed data source to match

[stephybun]

Thanks @dvob and @manicminer LGTM 🍕

[dvob]

@manicminer Thank you for finalizing this PR

[github-actions]

This functionality has been released in v3.29.0 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]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.