Draft: gitlab-ci: minimal jobs per ABI: amd64 arm64 ppc64le s390x

These are some new ABI-specific jobs based on the new GitLab CI Runners provided by OSUOSL. Once they are ironed out, they can be enabled globally on Tor's GitLab instance, and used for any/all jobs. This merge request just minimally adds new jobs, there are lots of possibilities, like running Android emulators, etc.

Since these are Debian jobs, the ABI names are taken from Debian. @ahf @anarcat-admin