[matter] do not print useless "MATTER_PACKAGE_NAMES = blah"
[entropy.client] extend Client.calculate_updates() to return critical updates info

calculate_updates() now returns a dictionary containing the same pieces of
information available before. In addition, it now also returns if critical
updates were found and returned by the method itself.
This is particularly useful for enforcing relaxed deps calculation in case
of critical updates (which is what happens now).

This commit breaks the Entropy Client API.
[entropy.const] drop /var/run/entropy/entropy.lock file and directory handling

This is no longer used by Entropy, which does use a more fine grained locking
instead.
[Rigo] ApplicationsViewController: sort category and package set entries