sourceSecondsDuration endpoint

[wohlner]

For any given account, we need an endpoint to query the sourceSecondsDuration for all streams created thus far in an active billing cycle and at the end of the billing cycle.

sourceSecondsDuration for the active billing cycle will be displayed on the usage tracking page in the livepeer.com admin and must be updated at least daily. sourceSecondsDuration will also be used at the end of the billing cycle for billing via our Stripe integration. To get an accurate count, we will need to query for streams with a parent id for a given account.

The billing cycle is not the first of the calendar month to the end of the calendar month. The billing cycle should be able to be set arbitrarily.

[adamsoffer]

@wohlner heads up I just transferred this issue to the livepeer/livepeer-com repo.