Added support for IP Check

[BlitzOffline]

Added a new setting: ip-mode. This new option allows giving rewards to all, none or 1 of the players that share an IP address.

# Select what happens when there are multiple players logged in with the same IP address.
# ALL - gives rewards to all players even if they share an IP address.
# RANDOM - gives rewards to one random player from the players sharing an IP address.
# FIRST - gives rewards to one player from the players sharing an IP address. The player is chosen based on alphabetical order.
# LAST - gives rewards to one player from the players sharing an IP address. The player is chosen based on reversed alphabetical order.
# NONE - do not give rewards at all to players that share an IP address.
ip-mode=ALL