add turkish to crowd-sourced languages

closes CNVS-11428

test plan:
* change your user settings to Turkish, and verify that the
  new translations appear properly

Change-Id: I7d21a8c32c1e2a80b8bd90e3fc32afc0b8211ab8
Reviewed-on: https://gerrit.instructure.com/30715
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Brian Palmer <brianp@instructure.com>