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

The cfg_peers external declaration was moved to the main file instead
of the type one. A few types were still missing from the proto, causing
warnings in the functions prototypes (proxy, stick_table).
diff --git a/src/mworker.c b/src/mworker.c
index eeedb4c..091a6df 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -22,12 +22,12 @@
 #include <haproxy/list.h>
 #include <haproxy/listener.h>
 #include <haproxy/mworker.h>
+#include <haproxy/peers.h>
 #include <haproxy/signal.h>
 #include <haproxy/version.h>
 
 #include <types/cli.h>
 #include <haproxy/global.h>
-#include <types/peers.h>
 
 #include <proto/cli.h>
 #include <haproxy/fd.h>