Update ownership sync jobs to use repo-tools instead of testeng-ci

[dianakhuang]

testeng-ci was deprecated and moved into openedx-unsupported. The main use for this repo was the pull_request_creator, which has been migrated into the repository https://github.com/openedx/repo-tools/tree/master/edx_repo_tools/pull_request_creator

As of right now, the old links should still continue to work and nothing is broken, but testeng-ci is not maintained and will not get Python upgrades, etc.