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

There's no type file for this trivial one. The unneeded dependency on
htx.h was dropped.
diff --git a/src/da.c b/src/da.c
index 20afdfc..ab36fa9 100644
--- a/src/da.c
+++ b/src/da.c
@@ -4,10 +4,10 @@
 #include <common/cfgparse.h>
 #include <haproxy/errors.h>
 #include <haproxy/http.h>
+#include <haproxy/http_fetch.h>
 #include <haproxy/http_htx.h>
 #include <haproxy/global.h>
 #include <haproxy/arg.h>
-#include <proto/http_fetch.h>
 #include <proto/log.h>
 #include <proto/http_ana.h>
 #include <haproxy/sample.h>