Geo Nodes Vertex Neighbors / Edge angle improvements

Edge Angle: This node only detects edge angles on enclosed meshes. Yet it can't detect edge angles of planar polygons and/or planar edges without polygons. This needs to be improved.

Vertex Neighbors: This node is currently only able to output "Vertex Count" and "Face Count", thus limiting its potential uses. This node should be able to spew out the "immediate" neighboring vertices of a given Vertex including access to their positions. As of now, it's very hard to get Geo Nodes to understand convexity and concavity between edges as a correct negative/positive winding is impossible to calculate due to the lack of ability of calculating the dot-product between a vertex and its immediate Neighbours.