more monster balance documentation

[LyleSY]

Summary

Balance "more monster balance documentation"

Purpose of change

Clear documentation, progress on #71957

Describe the solution

Now armor and vision and melee dice number and size and aggression are done. Still to do: morale and move cost of actions

Describe alternatives you've considered

N/A

Testing

Documentation

Additional context

Inspired by a lot of time spent trying to figure out what these things mean