[PR] Mindhack rebalance

[Keiiro]

From an RP player perspective: I haven’t seen multiple security members be mindhacked in the same shift, let alone all of them; I imagine this change is mostly guided towards the classic server and I’ll try to adapt my opinion to that environment.

I agree with Ikea that an item exclusive for something as specific as counteracting anti-mindhacks is awkward and in a way it also nerfs mindhacks obtained through indirect mediums, such as those found in surplus crates or as a spy thief, so I don't think it's the best solution.

Having multiple existing anti-mindhack implants that can be recycled could also create a frustrating uncertainty issue around them, example:

1. A security officer dies and they cannot be cloned back.
   
2. Their body gets reclaimed and their anti-mindhack implant is left for anybody around to grab.
   
3. Later on the shift, an antag attempts to mindhack a random staff assistant. 
   
4. They fail because the staff assistant grabbed the anti-mindhack implant from the dead secoff from earlier.
   

I think that if anti-mindhacks are to be extended to more members of security, making them non-recyclable after death and inactive while the implanted person is below a certain health threshold is a good way to balance them.

As a small note, although this would be a rough solution, an overlay could show up who you can’t mindhack if you have a mindhack implant in your hand, preventing somebody from wasting it, or otherwise, the implant could just not be depleted if it’s used against someone with an active mindhack implant.