add roles and locale to lti2 launches

fixes PLAT-758

test-plan:
*do an lti2 launch
*it should include the roles and locale as params

Change-Id: I987b65b56eee503d5b142ee2a5197c8b36b14697
Reviewed-on: https://gerrit.instructure.com/44263
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brad Humphrey <brad@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Nathan Mills <nathanm@instructure.com>