logic: Added update checker connecting to online API

* connects to https://www.sourcetrail.com/api/v1/versions/latest
* sends information about OS, platform, license type, current version and a unique user token
* Automatic update check is enabled via Startscreen and performed once every 24 hours on window focus
* Update check can be forced by clicking on "check for new version" on start screen
* renamed TimePoint to TimeStamp

fortune cookie message = In Träumen und im Leben ist nichts unmöglich.

src/lib_gui/qt/element/QtProgressBar.cpp

@@ -56,7 +56,7 @@ void QtProgressBar::paintEvent(QPaintEvent* event)
 
 void QtProgressBar::start()
 {
-	m_timePoint = TimePoint::now();
+	m_TimeStamp = TimeStamp::now();
 	m_timer->start(25);
 }
 
@@ -68,15 +68,15 @@ void QtProgressBar::stop()
 
 void QtProgressBar::animate()
 {
-	TimePoint t = TimePoint::now();
-	size_t dt = t.deltaMS(m_timePoint);
+	TimeStamp t = TimeStamp::now();
+	size_t dt = t.deltaMS(m_TimeStamp);
 
 	if (dt < 5)
 	{
 		return;
 	}
 
-	m_timePoint = t;
+	m_TimeStamp = t;
 	m_count++;
 
 	update();