Implement a worker for batch exporting of usage logs

This will allow customers to request their usage logs for a repository or an entire namespace, and we can export the logs in a manner that doesn't absolutely destroy the database, with every step along the way timed.

endpoints/api/test/test_logs.py

@@ -0,0 +1,31 @@
+import time
+
+from mock import patch
+
+from app import export_action_logs_queue
+from endpoints.api.test.shared import conduct_api_call
+from endpoints.api.logs import ExportOrgLogs
+from endpoints.test.shared import client_with_identity
+
+from test.fixtures import *
+
+def test_export_logs(client):
+  with client_with_identity('devtable', client) as cl:
+    assert export_action_logs_queue.get() is None
+
+    timecode = time.time()
+    def get_time():
+      return timecode - 2
+
+    with patch('time.time', get_time):
+      # Call to export logs.
+      body = {
+        'callback_url': 'http://some/url',
+        'callback_email': 'a@b.com',
+      }
+
+      conduct_api_call(cl, ExportOrgLogs, 'POST', {'orgname': 'buynlarge'},
+                       body, expected_code=200)
+
+      # Ensure the request was queued.
+      assert export_action_logs_queue.get() is not None