[Unknown Mod][Events] Allow to banish the month of the plague

[LeHerosInconnu]

Removed options that should be reintegrated into fheroes2.

world: ban plague month
This option can prevent "unintentional" reloads of the game.
It can also be interesting to decide to play some fairly strategic scenarios without the month of the plague spoiling the fun of playing.

This can be implemented directly in fheroes2.