Feature: Position notification on Left, Center, Right.

[ronyu21]

Position Left

• For desktop, notification transition in at left to right direction and transition out at right to left direction. All animation happens near the top of the viewport and stays at top left corner after transition in finished.
• For mobile, notification transition in at left to right direction and transition out at right to left direction. All animation happens near the bottom of the viewport and stays at bottom left corner after transition in finished.

Position Center

• For desktop, notification transition in at top to bottom direction and transition out at bottom to top direction. All animation happens near the top of the viewport and stays at top center after transition in finished.
• For mobile, notification transition in at bottom to top direction and transition out at top to bottom direction. All animation happens near the bottom of the viewport and stays at bottom center after transition in finished.

Position Right

• For desktop, notification transition in at right to left direction and transition out at left to right direction. All animation happens near the top of the viewport and stays at top right corner after transition in finished.
• For mobile, notification transition in at right to left direction and transition out at left to right direction. All animation happens near the bottom of the viewport and stays at bottom right corner after transition in finished.