Add option to set a hard limit on how many loot rats can be alive at a time.

Fix a bug when the mod is loaded in disabled state

- Rework spawn number options to pick a random number between a defined minimum and maximum
- Add option to spawn a barrel on death
- Add option to light a spawned barrel

Rework spawn timer options to pick a random number between chosen min and max values.

Fix bug where spawning would continue even if the mod was disabled in the mod options.