Add a mechanism to halt and resume connection

[nugget]

Since the AVR can only support a single telnet connection at a time, responsible client code should have a method for disconnecting and reconnecting voluntarily so that the user can connect with other apps (like the ARC-2 room correction software) with disrupting other services.

[smichalove]

Verified : Working: https://github.com/smichalove/Anthem60_turnon/blob/main/AVM60onviaIP.py