PrepCustomFileChallengeQuestions is the inner version of PrepFileChallengeQuestions without using a real guard file contracts, but rather custom parameters (mostly for manual testing).

PrepFileChallengeQuestions checks and prepares all shard questions in one setting.

PrepShardChallengeQuestions checks and prepares an amount of random challenge questions and returns the necessary guard proto struct.

SendChallengeQuestions combines all shard questions in a file and sends to guard service.