[Bicep Extensibility] Deprecating the term provider in favor of extension

[shenglol]

We plan to deprecate the term provider in Bicep and our public documentation, replacing it with extension for the following reasons:

• Improve Clarity: The term provider is commonly associated with Azure Resource Providers within the context of ARM. Using provider to refer to a Bicep extensibility provider could lead to confusion. Conversely, the term extension is more intuitive and clearly conveys its purpose within the Bicep Extensibility context.
• Avoid API Name Clash: To support deployment stacks as part of the Bicep Extensibility GA plan, we need to update the Microsoft.Resource/deployments API by adding a property to capture Bicep extensibility provider information in the API output. However, currently, the API output already includes a providers property, which lists the Azure Resource Providers involved in a template deployment. By using extensions instead, we can avoid conflicts with the existing providers property.

To avoid breaking changes for customers, we will follow these deprecation steps:

• Update Bicep:
  • Emit warnings for the provider keyword and provide a code fix to help customers migrate to the extension keyword (Replace the provider keyword with the extension keyword #14378).
  • Add a publish-extension command and mark the publish-provider command as being deprecated (Deprecate publish-provider #14376).
  • Add extensions and extensionAliases in bicepconfig.json and deprecate providers and providerAliases (Deprecate providers, providerAliases, and implicitProviders in Bicep configuration #14377).
• Allow a couple of months for customers to adopt the new Bicep version containing the above changes.
• Revise public documentation to use the term extension.
• Wait a few more months before officially dropping support for provider in Bicep.