Ref #4
This commit adds an active monitoring of the current public IP. If a
change is detected, then a message is sent to the given Telegram
channel. Add a few tests for the main monitoring logic.
Ref #3
This commit uses a GET query to ifconfig.me in order to get the current
public IP. It also modifies the initialization message to send the
current public IP to the Telegram channel instead of a simple message.
