Allow HttpClient to remember my cookie

[wchen-r7]

When the target host sets a cookie, the Httpclient should remember it. That way in the module I won't have to manually extract it, and then put it in the next request.

If some for reason the module decides to send to different hosts, the HttpClient mixin should know which one to use. Also, as you can see only send_request_cgi() uses this feature, I don't think send_request_raw should be using it because it's supposed to be the most basic form of send_request_*.

For testing, use test/modules/auxiliary/test/cookie_test.rb, and then you'll have to use wireshark to verify it's working properly. You can set the rhost to 208.118.237.137 if you want, that's metasploit.com.

[SeeRM #8706]

[jvennix-r7]

This PR looks useful but I see a couple things wrong:

• cookies need to be split and stored as key-value
• Set-cookie needs to behave like "replace-or-append" on a per-key basis, instead of "replace-all" approach now

Cookie jar implementations I have seen are not so simple, the spec is pretty long. Probably easiest to use a pre-existing gem to handle parsing/storing/serializing client-side cookies. This one looks minimal, tested, spec-compliant, and is MIT-licensed: https://github.com/sparklemotion/http-cookie

[wchen-r7]

Awright, let's close this one.