Add a way for knowing the springdoc-openapi made the request or not

[talentedasian]

It would be nice if it was possible to determine whether if springdoc-openapi made the request.

[talentedasian]

This is already possible through the Referer header name in the HttpServletRequest

[talentedasian]

Opening this issue again because the Referer can feasibly spoofed.

[bnasslahsen]

@talentedasian,

With the next release, you can add debug log level on:
org.springdoc.api.AbstractOpenApiResource