[systemd] make SystemdService instantiable from QML
[systemd] allow connection to system service manager
[systemd] allow assigning a SETUID helper

Through the helper executable that is SETUID root, regular user can
control a system service. The binary should accept a single argument,
one of 'start', 'stop', 'enable', 'disable' to invoke the respective
action.
[qmake] rename systemd user services path

Renamed from CREPORTER_SYSTEM_SYSTEMD_SERVICES to
CREPORTER_SYSTEM_SYSTEMD_USER_SERVICES.
[endurance] add endurance-collect script
[endurance] install systemd service and timer files
[endurance] add SETUID helper

Allows regular user to start and stop endurance snapshot gathering that
runs as a system service.
[endurance] allow switching snapshots collection on/off in config applet
[packaging] add sp-endurance to Requires
Incremented version