Universal way to get metadata about endpoint parameters.

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

I am not sure whether this [issue](https://github.com/dotnet/aspnetcore/issues/41421) is about the same problem I have.

See also [my question](https://stackoverflow.com/questions/72618163/what-is-the-most-universal-way-to-get-metadata-about-defined-endpoint-parameters) on Stack Overflow.

I need a universal way to get metadata about endpoint parameters. It's not too difficult for controller actions but not that simple for the endpoints with delegate implementations.

### Describe the solution you'd like

Well, I expect that Endpoint's metadata contains `Parameters` property like `ControllerActionDescription` does.

### Additional context

See also [my question](https://stackoverflow.com/questions/72618163/what-is-the-most-universal-way-to-get-metadata-about-defined-endpoint-parameters) on Stack Overflow.