Support `Cookie` in the headers

[Barbapapazes]

Hello 👋,

Despite the support of the key headers in the configuration, it's not possible to pass a key Cookie` within this configuration.

This is a known limitation of Scrappy but there is a workaround.

Cookies set via the Cookie header are not considered by the CookiesMiddleware. If you need to set cookies for a request, use the Request.cookies parameter. This is a known current limitation that is being worked on.

https://docs.scrapy.org/en/latest/topics/settings.html#default-request-headers:~:text=Cookies%20set%20via%20the%20Cookie%20header%20are%20not%20considered%20by%20the%20CookiesMiddleware.%20If%20you%20need%20to%20set%20cookies%20for%20a%20request%2C%20use%20the%20Request.cookies%20parameter.%20This%20is%20a%20known%20current%20limitation%20that%20is%20being%20worked%20on.

related to #79 (comment)