List models

Every model the generation endpoint accepts: display name, what it is best for, the kinds of input it takes, its largest resolution and longest duration, the fields it takes with their defaults and allowed values, and the credits a request that sends only a prompt costs, the same figure POST /api/v2/generations/estimate returns for it. When pricing.varies is true, other resolutions, durations or inputs cost differently: estimate those before submitting. Public.