Nice Villager Type Changer

Changes:

• restructured some code
• item used to change a villagers type can now be defined in the config menu
• changed default item used for changing a type to snow to minecraft:snow_block (was minecraft:snow)
• added lang file for en_us: Translations can be submitted on our Crowdin Page
• added check to prevent trying to change a villager type to the type it already has