rhtp and related: improved resilience

programs/umnp-rhtp-local.py

programs/umnp-rhtp.py

umnp/microcontroller/communication/udp_communicator.py

umnp/microcontroller/devices/network/ethernet.py

umnp/microcontroller/devices/network/ethernet_w5500.py

umnp/microcontroller/devices/network/udp.py

umnp/microcontroller/measurementdevice.py

umnp/microcontroller/sensors/lps28dfw/__init__.py

umnp/microcontroller/sensors/sht45/__init__.py

umnp/microcontroller/umock/machine/__init__.py