Better player faction AA emplacements

[Land-Strider]

Problem:

Rebel AA emplacements (ones that are purchased through commander menu) usually fail at recognizing the passing enemy aircraft.

This looks like a side effect of emplacement spawning distance and time around an enemy aircraft being narrow (default 1km spawn distance is too short for aircraft) or late (emplacement spawn logic spawns the static and the units around when an aircraft has already passed the above them).

This causes the AA emplacement either to get hit by a preset bombing run without even recognizing it, or the AA emplacements letting an aircraft pas through deep into rebel territory without any engagement.

Expected behavior:

AA emplacements complete their spawn procedures before an enemy aircraft gets into engagement radius, not after the aircraft has already completed the bombing run or passed above the AA emplacement, so the AA emplacement units have a chance at spotting the aircraft and engaging it in time.

Implementation suggestions:

• Have the rebel AA emplacements spawn in a larger radius around a flying enemy aircraft instead of the usual 1km. Up to 5km of spawn radius for AA emplacement spawn around enemy aircraft should be reasonable.
• For performance reasons, don't extend this spawn radius change to anything else.
  • Only an enemy aircraft should spawn only rebel AA emplacements within the larger radius.
  • If the AA emplacements start performing better as expected, consider limiting the number of simultaneous rebel AA emplacements presence.

[Land-Strider]

Added a parameter to increase the distance of rebel AA posts spawning around enemy aircraft, up to 5x of the Spawn Distance parameter setting in the Basic Parameters tab.
Also added enemy planes to spawn AA posts within this set distance, while previous enemy planes did not spawn any markers at all.

AA posts now shoot their static weapons at enemy aircraft more reliably instead of getting caught unprepared or not spawned at all.

There is one quirk that enemy paradrop planes don't seem toe get targeted by AA post soldiers carrying lock-on manpads while the static guns reliably shoot at these planes. The mentioned manpads lock on and shoot at all other aircraft types, though.

Even the 2x option seems to be performing quite well even on a direct hosted machine. Dedicated server performance should even be better. 3x, 4x and 5x options will be kept for a while for testing purposes.

Implemented in commit 55fddb7

The issue should stay open until further testing is passed.