Inconsistencies in secc/interface

[raoulKalkman]

In secc/controller/interface.py

I found some inconsistencies while writing my own implementation, they are as follows:

• get_dc_charge_parameters_{v2|dinspec| } and get_dc_charge_params_v20, get_dc_charge_loop_params_v20 follow different abbreviation methods
• in get_evse_present_voltage and get_evse_present_current the unit doesn't use the UnitSymbol class
• The is_evse_current_limit_achieved and is_evse_voltage_limit_achieved don't have their type hinting set to bool
• The function docs of get_dc_charge_parameters_dinspec and get_dc_charge_parameters both say they're only relevant for -2

Thank you for reading