Pylontech/ add State of Health - residualmA - Cycle

**Describe the problem you have/What new integration you would like**
Hello, and sorry my English is bad...
First of all, thanks to `functionpointer` for his work!
I would like the functions `State of Health`, `Number of batteries`, `residualmA` and `Cycle` be added.

**Please describe your use case for this integration and alternatives you've tried:**
To obtain this information, you must use the command `pwrsys` , `getpwr1` and 2, 3 ,.... , `stat1` and and 2, 3 ,....
If it's useful I can provide my personal file (I sent it by PM to @functionpointer on Discord)

**Additional context**

Start by locating the existing Pylontech integration and tracing how the pwrsys, getpwr1, and stat1 commands are handled. Confirm the protocol responses and determine how State of Health, battery count, residualmA, and Cycle should be exposed; done means these values are available through the integration with suitable validation.

Written by the indexing model from the issue text.