Add connection ID to track requests and responses in log

[droscy]

Having more than one device in config file, it was hard for me to track which clients communicate with which device, so I added a simple ID to the name of each connection in order the have that ID printed in every line of log. The ID is derived from url of modbus device.

INFO modbus-proxy.ModBus(192.168.0.10:502, 8ce6dd): Ready to accept requests on 0:11120
INFO modbus-proxy.ModBus(192.168.0.11:502, a633f1): Ready to accept requests on 0:11121
INFO modbus-proxy.Client(127.0.0.1:57240, 8ce6dd): new client connection
DEBUG modbus-proxy.Client(127.0.0.1:57240, 8ce6dd): received b'\x96\xac\x00\x00\x00\x06\x01\x03\x9c\x87\x00&'
INFO modbus-proxy.ModBus(192.168.0.10:502, 8ce6dd): connecting to modbus...
INFO modbus-proxy.ModBus(192.168.0.10:502, 8ce6dd): connected!
INFO modbus-proxy.ModBus(192.168.0.10:502, 8ce6dd): delay after connect: 0.5
INFO modbus-proxy.Client(127.0.0.1:43987, a633f1): new client connection
DEBUG modbus-proxy.Client(127.0.0.1:43987, a633f1): received b'\x96\xac\x00\x00\x00\x06\x01\x03\x9c\x87\x00&'