less strict set target

[ykc1n]

Way more units are allowed to set-target now.

This includes:

• Static defenses
• Bombers

This is partially to fix #5590 , since units that cant set-target will do nothing instead

However, there are also situations where these units would like to use set-target in general.

I'm not entirely sure why these units werent allowed from set-target in the first place, are there any issues that im not aware of?

[GoogleFrog]

Set target can be confusing, and it always costs a bit more performance.

• What happens when a structure has an attack and a set target command? I don't know the current behaviour, but at points one has been overridden randomly, or the turret has rapidly switched between the two.
• Bombers need attack commands to battle, much more than any other unit type. Pheonix especially needs movement to be able to fire. Iirc Likho and Magpie are already not excluded by the current restriction.
• A forgotten set target command on a bomber is a mistake waiting to happen. A move command to a bomber tends to mean "cancel attack run". If you have a lingering set target command, then the bomber is liable to waste its shot on the way to attacking something else.

So, todo:

• Check which bombers ever actually fire with a set target command.
• Add appropriate exceptions to the "move command issues set target" widget.
• Figure out whether there is ever a reason to set target and attack a turret. I can imagine some if the code works when both are applied, but does it work?