Implement Customer Billing Service API: Invoice Details

API used to get account invoice details for specific date range.
(Need to discuss if we need this api)

From business perspective:

• Most subscriber accounts will be created/managed in the TSA/AML Bing shell. Any account media spend in the TSA/AML Bing shell will be billed to TSA/AML with the intention for AML Finance to subsequently bill the subscriber the media spend from their merchant accounts.
• There will be a few subscribers that will provide us with their Bing Reseller API credentials. For those specific subscribers, accounts will be created/managed in the subscribers' Bing shell and invoiced directly by Bing.

I think we will want Consolidated Billing enabled.... but i will discuss that with the Bing AM.