Handle of invalid DateTime when format check fails

[jannejy]

OCPP Version

OCPP2.0.1

Describe the problem

Now while constructing DateTime from string if the format check fails, only a log error line is printed and then the request is processed with the invalid DateTime. For example, this happens when GetLogRequest is sent with empty-string timestamps. This applies as well to operator=

Describe your solution

Instead of printing the log line, throw a custom exception, process it and send CallError with verbose description (invalid string format to create DateTime, use RFC 3339 date format)

Additional context

No response