Create a utility rate_gold function

[mbernst]

I'm thinking about ways to enable traditional data capture workflows. Gold standards are a super common option. What if we created another utility rate_gold function? It takes in a dict input->correct answer as an argument, and then the utility function looks to see if any inputs from the tasks match the input, and if so check if the response matches a gold. It then takes sum(correct) and sends that to the rate() function.

[shirishgoyal]

It depends a lot on the data structure requester wants to use. So we let requester pass the data into the system and allow them to retrieve it later during approval and thus define any function to compare data with gold truth and rate accordingly. Also added a sample script on using gold data in tasks (using gold data for rating)