Implement smart edge type support

[philippjfr]

Adds support for various smart edge types based on the @tisoap/react-flow-smart-edge extension:

Type	Description
"bezier"	Smooth bezier curve (default).
"straight"	Straight line between nodes.
"step"	Orthogonal path with right angles.
"smoothstep"	Step path with rounded corners.
"smart_bezier"	Bezier curve that automatically routes around nodes.
"smart_straight"	Straight segments that automatically route around nodes.
"smart_step"	Step path that automatically routes around nodes.