Add some more base implementation layout.

+ Create the `executor` in the 'ExportsResourceImpl'
+ Add the `DataExportTask` for submitting to the executor
+ Add the `requestToken` call for getting a request
Add a unit test for data export failing.

+ Add the test
+ Implement `equals` for the `ApiResponse`
Add a status code to the `ApiResponse`.

Since the data exports endpoint uses the status code to
convey information about the current state of the export, we
need access to it.