Add broader support for Microsoft's Custom Connector annotations

Related to: https://github.com/aliencube/AzureFunctions.Extensions/issues/116

> There are already samples how to make use of this library to make some more advanced annotations for Custom Connectors in Logic Apps or Power Automate.
>
> It would be really cool to get support for trigger annotations along with dynamic schema and so on. Microsoft has it quite well documented here: https://docs.microsoft.com/en-us/connectors/custom-connectors/openapi-extensions
>
> In the past, there was a project called T-Rex which did exactly that, however it was only for ASP.NET on .NET Framework and doesn't support ASP.NET Core or Azure Functions.