Control files are out of sync

[scpeters]

Usually one of the control files for a specitic distro is sym-linked to ubuntu/debian/control, but neither the focal nor jammy control files is a sym-link, and there are differences between all 3 files.

• https://github.com/gazebo-release/gz-physics6-release/blob/main/focal/debian/control
• https://github.com/gazebo-release/gz-physics6-release/blob/main/jammy/debian/control
• https://github.com/gazebo-release/gz-physics6-release/blob/main/ubuntu/debian/control

We should synchronize the the files a bit and make one of them (probably jammy) a sym-link to ubuntu/debian/control.

[scpeters]

an initial step towards synchronization is in #15

[scpeters]

the ubuntu/debian/control file still has a bunch of Breaks and Replaces statements that have been removed from focal and jammy. @j-rivero I assume those aren't needed?

[j-rivero]

the ubuntu/debian/control file still has a bunch of Breaks and Replaces statements that have been removed from focal and jammy. @j-rivero I assume those aren't needed?

They were introduced as part of the ign -> gz transition and are used to replace ign packages by gz. I think it is good to preserve them.