Use ammo_effect_str_id instead of std::string

[Fris0uman]

Summary

None

Purpose of change

• Use ammo_effect_str_id instead of std::string
• will be necesssary to add on hit effects in Expand implementation of liquid ammo #72271
• Move "RECOVER_n" out of ammo_effect and into islot_ammo as a new int

Describe the solution

• Replace the thing with the other thing

• Replace the RECOVER_n pseudo flag string parsing with a recovery_chance entry

• Change how the probability is computed from 1 - (1/n) to n/100

• Update json to use the new system: I'm keeping the same number as I don't think anyone writing those json expected the probability to be 1-(1/n) rather than n/100

Describe alternatives you've considered

Testing

Compile without error
Load a new game without error

Additional context

Most of those hardcoded "effects" should probably be flags instead but that's out of scope for this PR

We can change the recovery values if we want, some values seem pretty low but I'm not sure

[Maleclypse]

Much clang angry.