REORG: http: move HTTP rules parsing to http_rules.c

These ones are mostly called from cfgparse.c for the parsing and do
not depend on the HTTP representation. The functions's prototypes
were moved to proto/http_rules.h, making this file work exactly like
tcp_rules. Ideally we should stop calling these functions directly
from cfgparse and register keywords, but there are a few cases where
that wouldn't work (stats http-request) so it's probably not worth
trying to go this far.
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index c000602..3cc622a 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -49,6 +49,7 @@
 #include <proto/channel.h>
 #include <proto/connection.h>
 #include <proto/fd.h>
+#include <proto/http_rules.h>
 #include <proto/listener.h>
 #include <proto/log.h>
 #include <proto/port_range.h>