Single Region Data Residency & Portal Azure AD Support

Changes for data residency and Azure AD support are now GA.

Data residency: All customer data stored in App Configuration now resides within the region where the original configuration store was created. Customer data will not be automatically replicated between Azure paired regions.

Azure AD: The App Configuration portal now allows you to switch between Access Keys and Azure AD for authentication when accessing configuration values and feature flags. Your current authentication method is displayed at the top of the blade, and can be switched easily by clicking on the "Switch to Azure AD" or "Switch to Access keys" button.

Please [let us know](https://github.com/Azure/AppConfiguration/issues/new) if you have any questions or feedback on these changes.