New Flag - Villager Invincible = True/False

### The Problem

Though not a problem this flag would allow for protecting Villagers within a Region. Preventing the occasional zombie horde wandering in or pillagers finding their way into a village killing all the villagers in a region intended for players to use.

### A Solution

Adding a new flag to protect villagers by making those within the region fully protected/invincible.

The flag would be a true false flag where the default is false

The flag could simply read as follows in the Flags list:
_Villager Invincible_

### Alternatives

One can use a command for this however it requires protecting each villager during the creation of said villager ruining the point of naturally spawned villagers and trade system

### Anything Else?

I can be reached out to directly on Discord at EchocallingEarth#0001 or here, if further info is needed or if testing of said flag would be needed.

Thank you for considering this new flag.