Improve subterranean harvester pathfinding

[Starkku]

This PR should allow MovementZone=Subterannean harvesters to access docks that are in areas closed off from normal pathfinding such as cliffs and islands. Whether or not it fixes all issues with such harvesters is another thing.

[github-actions]

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[CrimRecya]

It looks good. And I need to test whether it will be affected by the refinery on water surface.

[Coronia]

used Project Phantom as a test, but there're still some subterrenean miners getting stuck for unknown reason, mostly happened when they're trying to get to an ore field which is being harvested when they're on their ways

1 - stuck at ore field

2 - stuck at slope

[mevitar]

Did some games against the AI with this, and at some random point the game dropped to like 1 fps. This happened several times, but lasted only few seconds (except for one game, which didn't seem to fix itself so i had to quit). I also haven't encountered this in any build other than this one.

All these games where it happened were me and AI playing as sides with subterranean harvesters. I'll try investigating further if they are indeed the cause.

[mevitar]

No fps drops this time, but game crashed with this build, can't tell the reason from except.txt
https://drive.google.com/file/d/1xd3PoLCVYi60-u0V2jbiQue97VGWkg5t

EDIT: can be ignored, it happens because of airstrike flare, and AirstrikeTarget not being cleared up properly

[mevitar]

Haven't had fps drops anymore, but these games were played at like 40-45 fps. The fps drops happened only in games with 60 fps, so that might have been related to how fast the game was processing, or the drawer that was used.

Had only sporadic cases of miners getting stuck, only in the lategame when the resources are mined out on most of the map. If Ollerus didn't point them out i wouldn't even be paying attention.
I'm not sure how much of that was due to them being subterranean miners and some bug making them forget to mine, or simply stopping mining because they can't find anyting to mine anymore.

[Starkku]

Attempted to further improve the behaviour but I suspect it won't fix every issue particularly with harvesters getting stuck if there's too many on single ore patch or refinery.

• Further improvements to rally point handling, should now reliably travel to rally point first if one is set instead of jumping to a ore patch if there's one nearby.
• Applied similar idle mode exceptions to subterranean harvesters as teleporting ones have.