Refactor OCPP callback captures

[Pietfried]

Describe the problem

The OCPP modules make frequent use of callbacks that they register as part of the libocpp ChargePoint class. The definition of the callbacks capture [this] most of the time, which is more than what actually nees to be captured.

EVerest Domain

OCPP, OCPP1.6, OCPP2.0.1

Affected EVerest Module

OCPP, OCPP201

Describe your solution

Change the callback definition to capture only the things that are actually needed. See #814 (comment)

Additional context

No response