Change Consent Key Parsing to Enum

[Lucas0T]

Currently consent keys are handled as strings.
They should be parsed as enum at the latest at the validation step of the crtdl.

[juliangruendner]

@Lucas0T i dont understand the relevance - why is the enum necessary here - can these keys not change with a new ontology anyway?

[Lucas0T]

@Lucas0T i dont understand the relevance - why is the enum necessary here - can these keys not change with a new ontology anyway?

Yes, but the keys should not change all the time. It is a question of type/code safety vs. dynamicity