windowrules: add rule group to map windows grouped (#3279)

* windows: add rule group to map windows grouped

* group rule: use `invade` to force open a window in a locked group

src/managers/KeybindManager.hpp

@@ -151,6 +151,7 @@ class CKeybindManager {
     static void     moveGroupWindow(std::string);
     static void     moveWindowOrGroup(std::string);
     static void     setIgnoreGroupLock(std::string);
+    static void     denyWindowFromGroup(std::string);
     static void     global(std::string);
 
     friend class CCompositor;