[2.X] Add an additional TechnologyTrigger for a damaged/destroyed entity

[MrSmoothieHuman]

As it says on the tin, a new research_trigger type that only activates when a building has been damaged and needs repairing, and/or when an entity has been destroyed would be a nice addition and would allow for a lot more customization in mods in regards to trigger technologies.
The main example (and the main reason why I made this request) is for repair packs, having them unlock when an entity gets damaged sounds a lot better to me personally; another example that mods could implement is having a specific technology unlock when a player kills a biter, or other enemy.

I hope this sounds useful enough to implement in some capacity, and thank you for reading :]

[curiosity]

I have nothing against the request itself, but the idea of locking repair packs behind entity being damaged is just silly. That's when you want to already have them.

[MrSmoothieHuman]

thats fair enough tbh, the idea made sense in my head when first thinking about it, but time does what time is - but as you said, having some capacity of this would be super neat