Envoy-reader

- Clean up detection code and optimize calling endpoints (PR 64)

- Stop flooding Home Assistant log when trying to gather inverter data for Envoy running <3.9 firmware. These firmware do not support inverter data gathering

- Automatic retry when gathering Inverter data. Sometimes the Envoy will not return Inverter data, this retry will workaround this issue.

- HTTP requests to Envoys with firmware <3.9 was moved to `getData()`. Other firmwares the HTTP requests (except for Inverter data gathering) was already moved to `getData()` in previous release
- Move Inverter gathering to `getData()`
- To support gathering Inverter data I added an optional parameter for the EnvoyReader constructor. So that if Home Assistant config does not have inverters then this can be skipped.
- Removed `detect_model()` method calls from individual methods and runs only from `getData()`
- Removed `isDataRetrieved` boolean variable, as this is not used

- Remove update() method that Home Assistant previously used
- Change to raising exceptions when errors occur
- Replaced requests_async library with httpx

- This release is `0.17.0` plus the below fixes.
- Removal of the flag to force updates with every poll from Home Assistant. Since Home Assistant sensor code was not updated, it does not know about the `getData()` and does not retrieve data from the Envoy after the initial poll.
- Fixed a bug introduced in '0.17.0' that caused the failure to retrieve Production data for older Envoys (Firmware < 3.9)
- Added check to not retrieve Inverter data for older Envoys (Firmware < 3.9) as this data is not available

Note: It appears the versioning scheme did not conform to [PEP-440](https://www.python.org/dev/peps/pep-0440/), so these changes and the rest of the changes made in `0.17.1` and `0.17.2` will be made into a `0.18.0` release.