Move most of the net collection out of the core.

- Most units and signatures from the `net` collection
  are now in `compatibility-lib`.
- Most of the actual libraries are in the `net-lib`
  package.

original commit: 2b1fb036c6

pkgs/net-lib/info.rkt

@@ -0,0 +1,4 @@
+#lang setup/infotab
+
+(define collection 'multi)
+(define deps '("base"))

pkgs/net-lib/net/cgi.rkt

@@ -1,6 +1,6 @@
 #lang racket/base
 
-(require "uri-codec.rkt")
+(require net/uri-codec)
 
 (provide
 

pkgs/net-lib/net/cookie.rkt

@@ -351,5 +351,3 @@
 
 (define (valid-path? v)
   (and (string? v) (rfc2109:value? v)))
-
-;;; cookie-unit.rkt ends here

pkgs/net-lib/net/mime.rkt

@@ -28,7 +28,7 @@
 
 #lang racket/base
 
-(require racket/port "mime-util.rkt" "qp.rkt" "base64.rkt" "head.rkt")
+(require racket/port "mime-util.rkt" "qp.rkt" net/base64 net/head)
 
 (provide
  ;; -- exceptions raised --

pkgs/net-lib/net/smtp.rkt

@@ -1,6 +1,6 @@
 #lang racket/base
 
-(require racket/tcp "base64.rkt")
+(require racket/tcp net/base64)
 
 (provide smtp-sending-server
          smtp-send-message

pkgs/net-lib/net/ssl-tcp-unit.rkt

@@ -1,6 +1,6 @@
 #lang racket/base
 (provide make-ssl-tcp@)
-(require racket/unit "tcp-sig.rkt" openssl/mzssl)
+(require racket/unit net/tcp-sig openssl/mzssl)
 
 (define (make-ssl-tcp@
          server-cert-file server-key-file server-root-cert-files

pkgs/racket-pkgs/racket-doc/net/scribblings/cookie.scrbl

@@ -178,6 +178,10 @@ won't have a cookie set then first arrive at your site.
 
 @section{Cookie Unit}
 
+@margin-note{@racket[cookie@] and @racket[cookie^] are deprecated.
+They exist for backward-compatibility and will likely be removed in
+the future. New code should use the @racketmodname[net/cookie] module.}
+
 @defmodule[net/cookie-unit]
 
 @defthing[cookie@ unit?]{