REORG: include: move arg.h to haproxy/arg{,-t}.h

Almost no change was needed; chunk.h was replaced with buf-t.h.
It dpeends on types/vars.h and types/protocol_buffers.h.
diff --git a/src/http_acl.c b/src/http_acl.c
index 8ff4ab3..2fe7e85 100644
--- a/src/http_acl.c
+++ b/src/http_acl.c
@@ -26,7 +26,7 @@
 #include <types/global.h>
 
 #include <proto/acl.h>
-#include <proto/arg.h>
+#include <haproxy/arg.h>
 #include <proto/auth.h>
 #include <proto/pattern.h>