Simplify exclusion area polygons after their merging

[Indy2222]

Exclusion polygons are offsetted and overlaping polygons merged before map triangulation is computed. In the process, short polygon edges might be generated. Their removal would have a negligible impact on positional accuracy but a potentially big impact on the triangulation (both on triangulation performance and on path finding performance due to more triangles => larger search graph).

[github-actions]

There is no activity on the issue for some time. The issue will be automatically closed in 3 weeks.