WIP: Use optimize and complete sync for APT repos

[quba42]

What are the changes introduced in this pull request?

They allow for Katello to make use of the pulp_deb optimize sync mode, which uses exactly the same interface as the pulp_rpm optimize sync.

Considerations taken when implementing this change?

This requires pulp_deb 2.21 and pulpcore 3.21 as well as updated client rubygems. These versions will probably not be available in Katello for some time, so this PR is more for discussion for now.

What are the testing steps for this pull request?

There are three places where these changes can be used from:

• smart proxy page > Synchronize (drop down) > Optimize Sync or Complete Sync
• Repository page (of a deb type repo) > Select Action > Advanced Sync > Optimize Sync or Complete Sync > Sync
• Products page > Select products that include deb type repos > Select Action > Advanced Sync > Optimize Sync or Complete Sync

In each case, the corresponding underlying pulp sync task needs to be called with the correctly set optimize flag.