Add broader support for Microsoft's Custom Connector annotations

[justinyoo]

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.

[filcole]

I would like to be able to support the x-ms-capabilities top level entry as explained here: https://docs.microsoft.com/en-us/connectors/custom-connectors/test-connection , e.g.

"x-ms-capabilities": {
    "testConnection": {
      "operationId": "TestMyAPIConnection",
      "parameters": {}
    }
  }