WIP basic_lti_outbound gem extraction

Change-Id: Icb8f78bdd5f41e4eae18b30d1a4cfc7dd9942057
Reviewed-on: https://gerrit.instructure.com/28722
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Raphael Weiner <rweiner@pivotallabs.com>
Product-Review: Brad Humphrey <brad@instructure.com>
QA-Review: Brad Humphrey <brad@instructure.com>