This PR adds the missing Water Heater device to matter-devices.xml.

The description was generated using the Alchemy tool
(https://github.com/project-chip/alchemy) with the following command:

`alchemy zap --attribute="in-progress"  --sdkRoot=./connectedhomeip/
--specRoot=./connectedhomeip-spec/
./connectedhomeip-spec/src/device_types/WaterHeater.adoc`

I manually fixed the device nae from `Matter Water Heater` to `Water
Heater`.

This PR refactors the energy-management-app into 2 separate endpoints
(one for EVSE and another for WaterHeater).

This is the first step in making this app spec-conformant.

`TC_DeviceBasicComposition.py` failed on this app before this PR and now passes.

Changes:
* Split Water Heater and EVSE into two separate endpoints (1 and 2).
  Updated zap and code.
* Dinamically disable unused endpoint at runtime. Based on the app choice
  (command line argument on linux or #define in ESP32 or SIlabs), initialize
  the clusters in the correct endpoint and disable the other endpoint.
  For example, for Water Heater, initialize clusters on endpoint 2 and
  disable endpoint 1 (EVSE).
* Refactor/move the init code related to ElectricalSensor (PowerTopology, EPM and EEM) from inside EVSE
  into ElectricalSensorInit.h/.cpp so they can be easier to reuse by both WaterHeater and EVSE.
* Refactor/move DEM cluster init code into its own file so it can be
  better reused outside EVSE.

Test performed:
1. Check basic composition for EVSE:
```
scripts/run_in_python_env.sh out/python_env './scripts/tests/run_python_test.py --app ./out/linux-x64-energy-management-no-ble/chip-energy-management-app --app-args "--application evse --trace-to json:log" --script src/python_testing/TC_DeviceBasicComposition.py --script-args "--qr-code MT:-24J0AFN00KA0648G00"'
```

2. Check basic composition for WaterHeater:
```
scripts/run_in_python_env.sh out/python_env './scripts/tests/run_python_test.py --app ./out/linux-x64-energy-management-no-ble/chip-energy-management-app --app-args "--application water-heater --trace-to json:log" --script src/python_testing/TC_DeviceBasicComposition.py --script-args "--qr-code MT:-24J0AFN00KA0648G00"'
```

3. Check app against `TC_EEVSE_2_6.py`:
```
rm -f evse.bin; ./out/linux-x64-energy-management-no-ble/chip-energy-management-app --enable-key 000102030405060708090a0b0c0d0e0f --KVS evse.bin --featureSet 0x3d

python src/python_testing/TC_EEVSE_2_6.py --endpoint 1 -m on-network -n 1234 -p 20202021 -d 3840 --hex-arg enableKey:000102030405060708090a0b0c0d0e0f
```