[ui] Add a "Reload All Nodes" menu to reload all the plugins' nodes

"Reload All Nodes" will reload all the descriptions for `NodePlugins`
that are part of loaded plugins, whether they are registered or not.

Once the reload of the descriptions has been performed, the node instances
from the current graph will be reloaded as well to reflect any change
in the description.

meshroom/ui/qml/Application.qml

@@ -552,6 +552,15 @@ Page {
         }
     }
 
+    Action {
+        id: reloadAllNodesAction
+        property string tooltip: "Reload all the node descriptions for all the registered plugins"
+        text: "Reload All Nodes"
+        onTriggered: {
+            _reconstruction.reloadAllNodes()
+        }
+    }
+
     Action {
         id: undoAction
 
@@ -830,6 +839,12 @@ Page {
                         ToolTip.visible: hovered
                         ToolTip.text: removeImagesFromAllGroupsAction.tooltip
                     }
+
+                    MenuItem {
+                        action: reloadAllNodesAction
+                        ToolTip.visible: hovered
+                        ToolTip.text: reloadAllNodesAction.tooltip
+                    }
                 }
                 MenuSeparator { }
                 Action {

meshroom/ui/reconstruction.py

@@ -552,6 +552,19 @@ class Reconstruction(UIGraph):
         nodes = self._graph.dfsOnDiscover(startNodes=[self._cameraInit], reverse=True)[0]
         self.setActiveNodes(nodes)
 
+    @Slot()
+    def reloadAllNodes(self):
+        """
+        Reload all the NodePlugins from all the registered plugins.
+        The nodes in the graph will be updated to match the changes in the description, if
+        there was any.
+        """
+        for plugin in meshroom.core.pluginManager.getPlugins().values():
+            for node in plugin.nodes.values():
+                node.reload()
+
+        self._graph.reloadAllNodes()
+
     @Slot()
     @Slot(str)
     def new(self, pipeline=None):