[Balance] Defending Infantry Cap

I suggest to increase the infantry deployment stock cap to 6 and the infantry generation rate up for the defender. The reason for this is that infantry are killed very quickly by enemy anti-infantry weapons and, on some maps, there are many trenches to be filled - but the rate of filling them is heavily stunted by the 4 unit stock cap.

Also, against some enemies, the healing tent seems to be totally ineffective.

I’m not sure what the MASH is supposed to be good for. Almost everything that kills infantry does so fast enough that healing them afterwards seems unhelpful.

On the other hand, I’ve had games where I spammed MG attackers as fast as I could and still couldn’t kill all the infantry the AI deployed. Might just be the map settings let the defenders have all the infantry spam they wanted.