Add nodes for modifying vector paths

Similar to how Instance Index and Instance Position input nodes work, but for paths. See for example Blender's Position Node:
https://docs.blender.org/manual/en/latest/modeling/geometry_nodes/geometry/read/position.html

This will allow the displacement of points in a path. One should also be able to modify the color and weight along the path.

Proposed nodes:
- Path Index
- Path Position
- Path Color
- Path Weight

Each of them should have a corresponding setter node, and/or be allowed as input to the Transform and Stroke nodes.
https://docs.blender.org/manual/en/latest/modeling/geometry_nodes/geometry/write/set_position.html

Down the road bezier handles should be accessible too. The more access to path data the better.

Start by reviewing the existing Instance Index and Instance Position input nodes, then compare Blender's Position and Set Position node references linked in the issue. Determine how Path Index, Path Position, Path Color, and Path Weight should expose path data and how their setter or Transform and Stroke integration should be scoped. Done means the agreed path data access and modification nodes are implemented with corresponding coverage.

Escrito por el modelo de indexación a partir del texto del issue.