export/import/copy course tab configuration with external tools

test plan:
* create a course with an external tool (either configured
for the course or on an account-level) that adds a course
 navigation tab
* arrange the tabs in the course settings
* copy the course, or export the course and then import
 into a new course
* should retain the same tab configuration as the original course

fixes #CNVS-8866

Change-Id: I8ee7cb5bd2e098829994e63f4fbd1ca4d0afd701
Reviewed-on: https://gerrit.instructure.com/32906
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Mark Severson <markse@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>