REORG: include: move payload.h to haproxy/payload.h

There's no type file, it only contains fetch_rdp_cookie_name() and
val_payload_lv() which probably ought to move somewhere else instead
of staying there.
diff --git a/src/backend.c b/src/backend.c
index 0d18e15..6c6c26d 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -30,6 +30,7 @@
 #include <haproxy/lb_fwlc.h>
 #include <haproxy/lb_fwrr.h>
 #include <haproxy/obj_type.h>
+#include <haproxy/payload.h>
 #include <haproxy/ticks.h>
 #include <haproxy/time.h>
 #include <haproxy/namespace.h>
@@ -43,7 +44,6 @@
 #include <proto/checks.h>
 #include <proto/lb_map.h>
 #include <proto/log.h>
-#include <proto/payload.h>
 #include <haproxy/protocol.h>
 #include <proto/http_ana.h>
 #include <proto/proto_tcp.h>
diff --git a/src/hlua.c b/src/hlua.c
index a2743f9..69d84bd 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -36,6 +36,7 @@
 #include <haproxy/map.h>
 #include <haproxy/obj_type.h>
 #include <haproxy/pattern.h>
+#include <haproxy/payload.h>
 #include <haproxy/tools.h>
 
 #include <types/cli.h>
@@ -50,7 +51,6 @@
 #include <proto/stats.h>
 #include <proto/http_fetch.h>
 #include <proto/queue.h>
-#include <proto/payload.h>
 #include <proto/http_ana.h>
 #include <proto/sample.h>
 #include <proto/server.h>
diff --git a/src/payload.c b/src/payload.c
index eaf8f06..3d176d6 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -15,13 +15,13 @@
 
 #include <haproxy/api.h>
 #include <haproxy/net_helper.h>
+#include <haproxy/payload.h>
 #include <haproxy/pattern.h>
 #include <haproxy/htx.h>
 #include <proto/acl.h>
 #include <haproxy/arg.h>
 #include <proto/channel.h>
 #include <proto/connection.h>
-#include <proto/payload.h>
 #include <proto/sample.h>
 #include <proto/http_ana.h>