feat: add property "LastLaunchedTime"

1. reactor some utils implementation.
2. remove constexpr before `decltype(auto)` due to GCC bug.
refer: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102229

Signed-off-by: ComixHe <heyuming@deepin.org>

api/dbus/org.desktopspec.ApplicationManager1.Application.xml

@@ -16,6 +16,7 @@
         </property>
 
         <property name="AutoStart" type="b" access="readwrite"/>
+        <property name="LastLaunchedTime" type="t" access="read"/>
 
         <property name="Instances" type="ao" access="read">
             <annotation