Summary:
Without this kactivitymanagerd logs way too much information about the
users activities/actions (see the reported Debian bug as an example) by
default. Logging categories can be easily enabled by the developers that
are interested in this information.

This change uses the categories that were already defined in Debug.cpp,
using resources for database and utils related messages, activities for
activities for activities and ksm related, and applications for the
rest.

Debian-BUG: https://bugs.debian.org/897388

Test Plan: It builds

Reviewers: #plasma, lbeltrame, ivan

Reviewed By: #plasma, ivan

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D12656