Omnikdatalogger

In v1.7.3 we change the icon mdi:flash-circle to mdi:lightning-bolt-circle in data_fields.json due to deprecation.

Now it seems this icon is not yet availble we rename it to mdi:lightning-bolt-outline to prevent missing icons.

- Icon `mdi:flash-circle` was renamed to `mdi:lightning-bolt-circle` in `data_fields.json` due to deprecation.

- Solves an issue where a division by zero could occur when AC voltage is 0.

> This new release is mainly important for users of the MQTT module and use this with Home Assistant.

With the brand new Energy function in Home Assistant last month (2021.8) we now can also monitor gas consumption (2021.9).
An architectural change in the use of the `state_class` and `last_reset` attributes requires this update.

If you are using Home Assistant, make sure you have installed the latest update (at least 2021.9.0) before updating Omnik Data Logger.
There is no impact for other MQTT users.

Other remarkable stuff in this release:
- PVoutput now resets solar generation at midnight when used with a Dutch Smart Meter and will not wait until your inverter(s) provide data.
- Proces temperature from openweathermap with DSMR updates at night.

This is a pré release to introduce the new state_class required to reveal the new energy features of Home Assistant.
To work work with Home Assistant (over MQTT) at least version 2021.9.0 or or latest beta version is requirered.

With this new feature you can monitor DSMR Energy (Electricity) and Gas provided through omnikdatalogger.

Running this software on older functions will break functionallity.

Improves error handling when a list item in the config file is not returning a list value.