Easy "Set-Cookie" methods

[pfk84]

I'd suggest adding something like hansott/psr7-cookies for easy cookie handling without having to manually fiddle with adding "Set-Cookie" headers...

Sadly, there is no withCookies() method defined in PSR-7, only withCookieParams() for the request...

[clue]

@pfk84 Interesting suggestion! I agree having helpers such as the package above available can help in applications that need more control over setting HTTP cookies. In either case, we may want to add a chapter about HTTP cookies to our documentation to at least give some basic pointers 👍 PRs welcome if this is something you want to look into