add the first plugins

raven/plugins/domain/rmenu.py

@@ -0,0 +1,26 @@
+from typing import Callable
+
+from raven.plugins.domain.raction import RAction
+
+
+class RMenu():
+    def __init__(self, label: str):
+        super(RMenu, self).__init__()
+        self.label = label
+        self.actions = []
+        self.listeners = []
+
+    def add_action(self, action: RAction):
+        self.actions.append(action)
+        self._notify()
+
+    def clear(self):
+        self.actions.clear()
+        self._notify()
+
+    def _notify(self):
+        for listener in self.listeners:
+            listener()
+
+    def add_change_listener(self, listener: Callable[[], None]):
+        self.listeners.append(listener)