Add a new SW AI targetting method: Random

I know this sounds stupid, but there should be a method where the AI can fire its super weapon at a random area, even if the super weapon would end up at the AI's own base.

Why? It would make a good application for abnormal weather occurrences such as Ion storms, coming from either a storm generating building such as Yuri's castle (like in the map: Transylvania Trouble), or an unclickable terrain piece.

It can also be good for "gamble" super weapons or SW with a chance of a misfire. Not like jamming SWs or the SW buildings self destructing, but like missiles malfunctioning during travel and end up returning back to the firer's base, or miscalculating coodinates for firing a SW and end up firing at an unintentional spot.

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No new tags necessary, just adding a new value for the SW.AITargeting= flag.