Add default bindings for new file and directory

assets/keymaps/default.json

@@ -543,6 +543,8 @@
     "bindings": {
       "left": "project_panel::CollapseSelectedEntry",
       "right": "project_panel::ExpandSelectedEntry",
+      "cmd-n": "project_panel::NewFile",
+      "alt-cmd-n": "project_panel::NewDirectory",
       "cmd-x": "project_panel::Cut",
       "cmd-c": "project_panel::Copy",
       "cmd-v": "project_panel::Paste",