Growatt solar sensor data expansion with supporting documentation

**Describe the problem you have/What new integration you would like**

Growatt solar integration supports sensors for PV string 1 and 2 only.
I would love if we can add full support for all PV strings available under the RTU2 protocol as outlined in the following document from growatt @ page 25 under PV3. Items 1-10 are already integrated but items 11-34 are not available at the moment
https://www.photovoltaicsolar.in/Growatt_Manual/MAX%20Series%20Modbus%20RTU%20Protocol.pdf

**Please describe your use case for this integration and alternatives you've tried:**

Use case is to get access to all PV string data availabe via the modbus.
These are clearly documented in the above reference document and should hopefully be a simple addition

**Additional context**

Due to recent breaking changed to the growatt home assitant integration i believe we should see a rising demand for modbus access to the same sensor data however the current version does not support all PV string data

Thanks to all the devs past and current for your great work.


Read the Growatt MAX Series Modbus RTU Protocol PDF at page 25 under PV3, then inspect the existing Growatt integration to compare the supported PV string items 1–10 with items 11–34. Done means exposing the remaining documented PV string data through the integration and updating its supporting documentation.

Written by the indexing model from the issue text.