Add systemd unit for powerdevil

Then we can place it in the background slice.

Plasma-workspace targets will then "want" this service at the right
phase of bootup

CMakeLists.txt

@@ -12,6 +12,7 @@ set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH}  ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 
 include(ECMSetupVersion)
 include(ECMQtDeclareLoggingCategory)
+include(ECMConfiguredInstall)
 include(FeatureSummary)
 include(KDEInstallDirs)
 include(KDECMakeSettings)

daemon/CMakeLists.txt

@@ -184,3 +184,5 @@ set(HAVE_XCB ${XCB_FOUND})
 configure_file(config-powerdevil.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config-powerdevil.h )
 
 install(TARGETS powerdevilui ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})
+ecm_install_configured_files(INPUT plasma-powerdevil.service.in @ONLY DESTINATION
+        ${SYSTEMD_USER_UNIT_INSTALL_DIR})

daemon/plasma-powerdevil.service.in

+[Unit]
+Description=Powerdevil
+PartOf=graphical-session.target
+After=plasma-core.target
+
+[Service]
+ExecStart=@KDE_INSTALL_FULL_LIBEXECDIR@/org_kde_powerdevil
+Type=dbus
+BusName=org.kde.Solid.PowerManagement
+TimeoutSec=5sec
+Slice=background.slice
+Restart=on-failure

daemon/powerdevil.desktop.cmake

@@ -50,6 +50,7 @@ Name[zh_CN]=电源管理
 Name[zh_TW]=電源管理
 Exec=@KDE_INSTALL_FULL_LIBEXECDIR@/org_kde_powerdevil
 OnlyShowIn=KDE;
+X-systemd-skip=true
 
 Comment=Battery, Display and CPU power management and notification
 Comment[ar]=تنبيهات وإدارة طاقة المعالِج والعَرض والبطارية