Omnikdatalogger

- Fix: publish `last_reset` attribute before sending MQTT value payload.

The measurements published through MQTT do now have a required `state_class` attribute set to `measurement`
The device classes in `data_fields.json` have been updated.
The MQTT module has been adapted to publish the `last_reset` attribute, which is needed to make the omnikdatalogger integrate with Home Assistant.

You can set the `last_reset` payload by setting the `start_date` at the install date of your smart meter (DSMR terminal settings) and for your inverter setting `start_date` at the plant specific configuration section.

P.S. This release resolves issues with sensor entities not shown in the energy dashboard.

The measurements published through MQTT do now have a required `state_class` attribute set to `measurement`
The device classes in `data_fields.json` have been updated.
The MQTT module has been adapted to publish the `last_reset` attribute, which is needed to make the omnikdatalogger integrate with Home Assistant.

This minor update fixes a problem where omnikdatalogger will crash on a fatal first MQTT connection.
With this update omnikdatalogger will keep retrying the connection until a successful connection loop is set up.

This release fixes some minor bugs:
- Reading logger_entity from attribute legacy config entry while a specific attribute is configured.
- Processing updates during sun down using cache.

- bug from v1.5.3 seemed not to be fixed. Fixed with this release