New weapon type: EXPLOSION (or WARHEAD). doing what missiles do now, except spawning units - justonly emitting the explosion wave itself.
- using the missiles' own sensors as remote fuse would allow to implement somewhat more advanced sensors/ECM model and add the effect of sensor damage for heavy missiles.
- unified model: missile AI would use the "get in range, discharge" attack routine, affected by ECM, stealth, etc just like ships and drones are;
- it can be event-chained with BOLT/BALL weapons (see the next ticket) to implement warhead-assisted (including flak) weapons with radius damage without spawning full units, which is currently impossible.
- to actually use it with existing rulesets, we'd need to create warheads in weapons.XML and set them into mounts of respective missile units in units.CSV. The conversion is straightforward and thus can be automated with a Python script, however.