MEDIUM: stream-int/conn-stream: Move src/dst addresses in the conn-stream

The source and destination addresses at the applicative layer are moved from
the stream-interface to the conn-stream. This simplifies a bit the code and
it is a logicial step to remove the stream-interface.
diff --git a/src/frontend.c b/src/frontend.c
index c8fb3d2..3ae24f2 100644
--- a/src/frontend.c
+++ b/src/frontend.c
@@ -26,6 +26,8 @@
 #include <haproxy/api.h>
 #include <haproxy/arg.h>
 #include <haproxy/chunk.h>
+#include <haproxy/connection.h>
+#include <haproxy/cs_utils.h>
 #include <haproxy/fd.h>
 #include <haproxy/frontend.h>
 #include <haproxy/global.h>
@@ -62,7 +64,7 @@
 					s->do_log(s);
 		}
 		else if (conn) {
-			src = si_src(cs_si(s->csf));
+			src = cs_src(s->csf);
 			if (!src)
 				send_log(fe, LOG_INFO, "Connect from unknown source to listener %d (%s/%s)\n",
 					 l->luid, fe->id, (fe->mode == PR_MODE_HTTP) ? "HTTP" : "TCP");
@@ -73,7 +75,7 @@
 				switch (addr_to_str(src, pn, sizeof(pn))) {
 				case AF_INET:
 				case AF_INET6:
-					dst = si_dst(cs_si(s->csf));
+					dst = cs_dst(s->csf);
 					if (dst) {
 						addr_to_str(dst, sn, sizeof(sn));
 						port = get_host_port(dst);
@@ -113,7 +115,7 @@
 			}
 		}
 
-		src = si_src(cs_si(s->csf));
+		src = cs_src(s->csf);
 		if (!src) {
 			chunk_printf(&trash, "%08x:%s.accept(%04x)=%04x from [listener:%d] ALPN=%s\n",
 			             s->uniq_id, fe->id, (unsigned short)l->rx.fd, (unsigned short)conn->handle.fd,