Cleanup old dependencies that are not needed any more after an uninstall or upgrade

Suppose there is an extension A that depends on extension B. First you install A and B gets installed automatically as transitive dependency.

Uninstall

Then you uninstall A. Currently B remains installed even though you may not needed it. The uninstall job should ask the user whether she wants to keep B installed or not.

Upgrade

A new version of A is released, A'. This new version doesn't depend on B any more, but it has a dependency on C. You upgrade A to A' and C gets installed as transitive dependency of the new version. B remains installed though. The upgrade job should ask the user whether she wants to keep B installed or not.