[Request] Add attribute Summary

[JABirchall]

At the moment, most generated requests for OpenApi are done via attributes.
However, the summary is still done via docblock reflection.

I propose to add a summary Attribute to replace docblock reflection.

#[OpenApi\Summary(string: "The summary of the request.")]

This will be used to populate the summary paramter of the request definition.

From my breif look through the code, this would allow the project to drop phpdocumentor/reflection-docblock dependancy