Optimize data structure and code while keeping backward compatibility

[vinothpandian]

The current implementation has to split eraser and pen strokes during render. This is reducing the performance (obviously) of the component.

• Update CanvasPath to have both eraser and pen strokes separately (Reduce time complexity)
• Update undo/redo to action based instead of replicating data (Reduce space complexity)
• Keep backward compatibility by adding a split method in loadPaths