REORG: tcp-rules: move tcp rules processing to their own file

There's no more reason to keep tcp rules processing inside proto_tcp.c
given that there is nothing in common there except these 3 letters : tcp.
The tcp rules are in fact connection, session and content processing rules.
Let's move them to "tcp-rules" and let them live their life there.
diff --git a/src/session.c b/src/session.c
index 93fdf52..8c85083 100644
--- a/src/session.c
+++ b/src/session.c
@@ -22,11 +22,11 @@
 #include <proto/listener.h>
 #include <proto/log.h>
 #include <proto/proto_http.h>
-#include <proto/proto_tcp.h>
 #include <proto/proxy.h>
 #include <proto/raw_sock.h>
 #include <proto/session.h>
 #include <proto/stream.h>
+#include <proto/tcp_rules.h>
 #include <proto/vars.h>
 
 struct pool_head *pool2_session;