Add application role 'Sample'

Sample hotkey which requires access to CGuiApplication, did not yet
set a application role. Since there was no corresponding role for
samples, I added one and set it in sample hotkey.

src/blackmisc/applicationinfo.h

@@ -32,7 +32,8 @@ namespace BlackMisc
             PilotClientCore,
             PilotClientGui,
             MappingTool,
-            UnitTest
+            UnitTest,
+            Sample
         };
 
         //! Flags describing application modes