screen: move to Terminal submenu

Part of a wider housekeeping effort on the packages repository.

Signed-off-by: Alberto Bursi <alberto.bursi@outlook.it>

utils/screen/Makefile

@@ -23,6 +23,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/screen
   SECTION:=utils
   CATEGORY:=Utilities
+  SUBMENU:=Terminal
   DEPENDS:=+libncurses
   TITLE:=Full-screen terminal window manager
   URL:=http://www.gnu.org/software/screen/