feat: add debug coordinate overlay

Makes debugging issues in conversion from screen space
to diagram space easier.

Only adding english translations as I do not speak the
other languages.

src/i18n/locales/en.js

@@ -59,6 +59,13 @@ const en = {
     show_timeline: "Show timeline",
     autosave: "Autosave",
     panning: "Panning",
+    show_debug_coordinates: "Show debug coordinates",
+    transform: "Transform",
+    viewbox: "View Box",
+    cursor_coordinates: "Cursor Coordinates",
+    coordinate_space: "Space",
+    coordinate_space_screen: "Screen",
+    coordinate_space_diagram: "Diagram",
     table_width: "Table width",
     language: "Language",
     flush_storage: "Flush storage",