Set the mouse cursor in the canvas based on the current tool and its state (#480)

* Add FrontendMouseCursor and DisplayMouseCursor

* Add update_cursor method to the Fsm trait and implement it for all tools

* Rename DisplayMouseCursor to UpdateMouseCursor

* Add 'To CSS Cursor Property' transform decorator and change the mouse cursor in the canvas based on the current tool and its state

* Implement update_cursor for Navigate tool properly

* Keep the cursor when dragging outside of the canvas

* Change the mouse cursor to 'zoom-in' when LMB dragging on canvas with Navigate tool

* Rename FrontendMouseCursor to MouseCursorIcon

* Rename 'event' to 'e' and replace v-on with @

* Change the definition of the MouseCursorIcon type in TS

* Replace switch with dictionary look-up

* Move the definition of MouseCursorIcon closer to where it's used

editor/src/viewport_tools/tool_message.rs

@@ -49,5 +49,6 @@ pub enum ToolMessage {
 	#[child]
 	Shape(ShapeMessage),
 	SwapColors,
+	UpdateCursor,
 	UpdateHints,
 }