docs: Update README for Ecowitt pre-release, expanded sensor support, and guidance
Update the README to reflect current development and provide clearer user guidance:
- Announce active Ecowitt support in the v2.0.0pre1 pre-release version.
- Expand the "Supported sensors" section with details on WSLink protocol specific sensors,
including additional channels (CH2/CH3), WBGT, heat index, wind chill,
sensor battery levels, and HCHO/VOC air-quality sensors (WH46).
- Clarify WSLink configuration, warnings, and quick recommendations.
- Correct the manual installation path for custom components and improve general readability.
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- Add support for SWS 10500 and Pocasi Meteo
- Announce upcoming Ecowitt support and integration rename
- Clarify WSLink SSL proxy requirements and upgrade instructions
Adds download badges to the README for better visibility
and includes zip release and filename options in the HACS
manifest to enable direct downloads through HACS.