CLEANUP: include: tree-wide alphabetical sort of include files

This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
diff --git a/src/payload.c b/src/payload.c
index d9b3107..7feea16 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -15,13 +15,13 @@
 
 #include <haproxy/acl.h>
 #include <haproxy/api.h>
+#include <haproxy/arg.h>
 #include <haproxy/channel.h>
 #include <haproxy/connection.h>
+#include <haproxy/htx.h>
 #include <haproxy/net_helper.h>
-#include <haproxy/payload.h>
 #include <haproxy/pattern.h>
-#include <haproxy/htx.h>
-#include <haproxy/arg.h>
+#include <haproxy/payload.h>
 #include <haproxy/sample.h>