npc-cap flag request

[KujouMolean]

PlotSquared Feature Suggestion:
Add "npc-cap" flag that can limit the villager amount. The villagers could cause unbelievable lag since 1.14. I want that players raise other animals instead of too many lag causer -- villagers. I think it's useful for 1.14+ servers.

How should it be implemented?
Just like "mob-cap" or "animal-cap". Cancel villager's spawning if the amount of villager in the plot reached npc-cap.

Additional context
Nothing.

Checklist:

• I made sure there are no duplicates of my suggestion (Use search)
• I made sure my suggestion does not exist yet (Check the wiki)
• I made sure my suggestion is useful for the majority of PlotSquared users

[NotMyFault]

Villagers are covered by the mob-cap and entity-cap flag.