Patch Usage Details API to enable date filtering for MCA customers

To make Usage Details API date-based filtering work for MCA customers, the API requires two additional query string parameters.

Unfortunately, the source OpenAPI spec omits the required startDate and endDate, and is unavailable for the generated clients. So we decided to fork the https://github.com/Azure/azure-sdk-for-go repo and add the missing params as a temporary measure.

For the long-term, we're getting in touch with Microsoft to include the missing params in the spec, so future releases will not require any patch.