REORG: include: move h1_htx.h to haproxy/h1_htx.h

This one didn't have a type file. A few missing includes were
added (htx, types).
diff --git a/src/h1_htx.c b/src/h1_htx.c
index 1f0dddb..b27ddca 100644
--- a/src/h1_htx.c
+++ b/src/h1_htx.c
@@ -13,11 +13,10 @@
 #include <haproxy/api.h>
 #include <common/cfgparse.h>
 #include <haproxy/h1.h>
+#include <haproxy/h1_htx.h>
 #include <haproxy/http.h>
 #include <haproxy/htx.h>
 
-#include <proto/h1_htx.h>
-
 /* Estimate the size of the HTX headers after the parsing, including the EOH. */
 static size_t h1_eval_htx_hdrs_size(const struct http_hdr *hdrs)
 {