Enable Context Help (Shift+F1) using "QT's - What's This"

... adds "What's this" to (hopefully) most of the widgets (please report
on missing ones)
... defines draft "Whats' this" texts including a
context specific WikiLink

.. Help Key for all platforms is <Shift>+<F1> + in some widgets
"RightMouse - Click"

... Tested on Win and Mac (On Mac QtMacButton seems not supporting
"What's this") - so here <Shift>+<F1> has no result.

... ToDo: Create final texts and links based on the to be updated 3.11
Wiki

src/SplitActivityWizard.cpp

@@ -20,6 +20,7 @@
 #include "MainWindow.h"
 #include "Athlete.h"
 #include "Context.h"
+#include "HelpWhatsThis.h"
 
 // Minimum gap in recording to find a natural break to split
 static const double defaultMinimumGap = 1; // 1 minute
@@ -44,6 +45,10 @@ SplitActivityWizard::SplitActivityWizard(Context *context) : QWizard(context->ma
     // title
     setWindowTitle(tr("Split Ride"));
 
+    // help
+    HelpWhatsThis *help = new HelpWhatsThis(this);
+    this->setWhatsThis(help->getWhatsThisText(HelpWhatsThis::MenuBar_Activity_SplitRide));
+
     // set ride - unconst since we will wipe it away eventually
     rideItem = const_cast<RideItem*>(context->currentRideItem());