PIPSolar integration add output

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

Please add to integration pipsolar output entity.
For bulk voltage.
for example with this name:
battery_bulk_voltage
On my inverter is a parameter 26, units are Volts and range is from 48.0 to 58.4, increment 0.1, only akceptable for battery type USE.

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

This parameter is missing for integration outputs.
**Additional context**

No files or tests are mentioned. Start by locating the PIPSolar integration's output definitions and checking how inverter parameter 26 is represented; done means exposing a bulk-voltage output with the requested name, units, range, increment, and battery-type restriction.

Written by the indexing model from the issue text.