Jira issue: https://storjlabs.atlassian.net/browse/USR-820
The bonus for depositing STORJ tokens is now added as to the Stripe
balance instead of the to `credits` DB table on the satellite.
Existing unspent bonuses in the `credits` DB table are still processed
as usual when generating invoices. They will be migrated to the Stripe
balance with a separate change.
The bonus is added to the Stripe balance with a separate Credit
transaction. The balance transactions for the deposit and the bonus can
be differentiate by their different description.
The billing history is modified to list the bonus from the Stripe
transactions list.
The workflow for depositing STORJ tokens to the Stripe balance is
improved to survive failures in the middle of the process.
Change-Id: I6a1017984eae34e97c580f9093f7e51ca417b962
