Added these features:
- Horse variants for rental (can be choosen by the player)
- Rented horse tp call back (horse gets teleported back to the player if far away; value can be modified in the config.yml)
- Anti-theft: A horse can only be ridden by the player who rented it (Can by tured off in the config.yml)
- The number of horses you can rent at a time can be limited in the config.yml