Add note key nudge function

- Notes must be clicked in order to engage the nudge function for that note
-- This status is indicated by a green border around the note
-- Clicking the note or another note will turn off nudging for that note
- Also prevent notes from being nudged outside of the image borders

app/javascript/src/styles/base/040_colors.css

@@ -117,6 +117,7 @@
   --note-box-background: transparent;
   --note-box-inner-border: 1px solid black;
   --unsaved-note-box-inner-border: 1px solid red;
+  --movable-note-box-inner-border: 1px solid green;
   --note-preview-border: 1px solid red;
   --note-preview-background: white;
   --note-highlight-color: blue;