Transfer ownership of Backport module

Note: I'm primarily creating this issue for posterity sake and to create a record that informs the other d.o webmasters of potential changes.

I recently became a co-maintainer of https://www.drupal.org/project/service_container and in my review of the issues/code, I recently created #2947485: Depend on Composer to figure out how this module should move forward.

In it, I realized that it may be more beneficial to simply deprecate that module and replace it with a new one where a name is more semantic with its functionality.

I looked up https://www.drupal.org/project/backport and saw that it's currently owned by "Unsupported Projects" and this namespace does make the most sense in regards to what I am proposing in that issue.

If we decide to go that route, I will take over https://www.drupal.org/project/backport.

If not, I will close this issue.