* Moved AccountsBilling controller to be owned by Billing
* Added org billing history endpoint
* Updated GetBillingInvoicesAsync to only retrieve paid, open, and uncollectible invoices, and added option to limit results
* Removed invoices and transactions from GetBillingAsync
* Limiting the number of invoices and transactions returned
* Moved Billing models to Billing namespace
* Split billing info and billing history objects
* Removed billing method GetBillingBalanceAndSourceAsync
* Removed unused using
* Cleaned up BillingInfo a bit
* Update migration scripts to use `CREATE OR ALTER` instead of checking for the `OBJECT_ID`
* Applying limit to aggregated invoices after they return from Stripe
