Introduces validateOutput function that validates and (right now blocked with a flag) converts the ids of the responses. Also introduces a pair of functions convertServerIDsToClientIDs (used in validateOutput and in tests) and convertClientIDsToServerIDs (only used in tests right now, will be used in the future diff for the input conversion).
Depends on D7710
This is going to display a human-readable name if it was provided when creating a validator or just display the validator definition if they don't have a name.