Adding cookie "Partitioned" flag

[Mickael-van-der-Beek]

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

Recently, browsers have added a new flag called Partitioned that allow cross-origin cookie setting on browsers where third party cookies are disabled (Safari, Firefox, future Chrome):

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#partitioned

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#partitioned_cookie

https://developer.mozilla.org/en-US/docs/Web/Privacy/Privacy_sandbox/Partitioned_cookies

Describe the solution you'd like

I'd love for the currently available Cookie class to support the new Partitioned flag.

Describe alternatives you've considered

It does not seem to be currently possible to set arbitrary strings as flags on Drogon cookies.