Handle multiple endpoints for graph resolution

[Desk3505]

As it stands in this version, the region exit is hardcoded in add_end_point_edge, the same as the function get_output_nodes should return. However, otherwise the algorithm stays in the RAP region and does not get out even with a singular exit point.
You will find this issue in file solver/rap_tracking line 100 -108.

[CHrlS98]

We need to test the function for endpoints to make sure it works as expected:

quactography/quactography/graph/utils.py

Line 6 in cd5accd

def get_output_nodes(mask, entry_node, propagation_direction, angle_rad):