Change: include fmt.h C++ headers in stdafx.h

This to prevent compilation issues between runs with and without precompiled
headers. Also remove the headers from the rest of the code base as they are
not needed there anymore, although they do relatively little harm.

Fix: Industry coverage area is no longer rectangular. (#7464)

AIs test station catchment in reverse to how players see station catchment.
This did not take account of non-rectangular station catchment areas, so AIs
could end up placing stations in locations that did not accept/deliver cargo.