Add config parameter `txpower` in inverters- and nrf context.
This enables overriding txpower default RF24_PA_MAX, in some cases
inverters require RF24_PA_LOW. For larger setups, txpower can be set per
inverter to be able to query a far away (max) and a near by (low) one from within
one instance.
Valid values can be:
* `txpower: 'max'` (corresponds to RF24_PA_MAX, default)
* `txpower: 'low'` (corresponds to RF24_PA_LOW)
Finally get rid of ahoy.py and integrate functionallity into the module
itself. Prepares for pipelines, adding pip installer or debian packaging.
Improve configuration adds commandline switches for:
* `--verbose, enabling verbose logging
* `--log-transactions`, outbut all rf raw data
Improve loop, now runs all queued commands per inverter within interval.
Skip sleep when interval is allready due.
