Port KSystemLog to KF5 and use journald as a backend

by Vyacheslav Matyushin for KDE

KSystemLog is a tool for viewing log files. It can display system logs, kernel logs as well as logs from various software, such as Apache, Cups, Samba, and others. Traditionally system logs were written to /var/log/syslog, but in a past few years many Linux distributions have switched to systemd. Systemd provides journald [1] - a component which manages system logs. The goal of the project is to port KSystemLog to KDE 5 frameworks and add the support for reading journald logs to KSystemLog.