feat: Add getSerial for room sensors

[CFenner]

This exposes the deviceID of room temp sensors and TRVs to be used in HA to identify the device.

https://github.com/somm15/PyViCare/blob/f8d1b446d3b74fb73d55552461c6e26b450923af/tests/response/zigbee_zk03839.json#L28

[CFenner]

Linter issues are unrelated to these changes and should be fixed in a separate PR:

************* Module PyViCare.PyViCareHeatPump
PyViCare/PyViCareHeatPump.py:112:4: W0105: String statement has no effect (pointless-string-statement)
PyViCare/PyViCareHeatPump.py:140:4: W0105: String statement has no effect (pointless-string-statement)

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Your code has been rated at 9.99/10

[CFenner]

Accessing device.sensors.temperature does work for temp sensors and TRVs (see test data). This is a workaround as long as Viessmann does not provide device.serial on zigged devices (see https://community.viessmann.de/t5/Feedback-API/Serial-Number-an-Gateways/td-p/410253)