Provide API method to determine instance datacenter

Provide API method to determine instance datacenter

To extend the idea provided at Add additional usage data for bulk API queries, handling bulk API data should be adjusted to understand datacenter locales as well. As an example, if you were looking to set up API extractions after a daily API limit is passed, knowing where the datacenter is helps integration providers understand when, exactly, an API limit will reset. Would it be possible to get AB, SJ, E, NL, SN, etc. passed as a result to calls like usage.json, or could we get a generic instance metadata call to provide information like this?