[REQUEST] Add support for OCPP 1.2

[juherr]

Hi,

To make the library more complete and feature-rich — and to position it as a potential base library for the Steve OSS CPMS — it would be great to add support for OCPP 1.2 (SOAP only).

The specification is available in the OCA archives: https://openchargealliance.org/my-oca/ocpp/

Thanks in advance!