Flag: follow shared dependencies on uninstall

[mattfarina]

In addition to following shared dependencies... it would be nice to be able to see which shared dependencies are still required by something else and skipping those.

Note, prior to trying to build this we should look at the feasibility of it and the user experience.

[viccuad]

This sounds like a specific case of removing unneeded charts, like a hypper autoremove that would remove all the charts that haven't been installed manually (for example, dependencies) and aren't being pulled in by other parent charts.

Would a hypper autoremove suffice?
Autoremove would be simpler to implement, as one doesn't need to keep track of which dependencies are not being pulled in by the removed parent package or other parent packages, and other dependencies that can be also removed but aren't related to the removal of the parent chart. We just remove all.
Also, autoremove solves nicely for prunning whole subtrees of dependencies, if all of those are not being pulled by anything. If we don't use autoremove, we would need to build ourselves the graph, to see if other parent charts depend on the same orphaned dependencies.