QmlJS: Add check for duplicated import

Add a soft check for duplicated Qml/JS imports which
adds a warning when a file contains imports that
duplicate the same URI / version or file path.

Change-Id: Ib9a1f8a90dd3cf469d90e83abc1d748901b1e353
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/libs/qmljs/qmljsstaticanalysismessage.cpp

@@ -240,6 +240,8 @@ StaticAnalysisMessages::StaticAnalysisMessages()
             tr("Referencing the parent of the root item is not supported in a Qt Quick UI form."));
     newMsg(StateCannotHaveChildItem, Error,
             tr("A State cannot have a child item (%1)."), 1);
+    newMsg(WarnDuplicateImport, Warning,
+           tr("Duplicate import (%1)."), 1);
 }
 
 } // anonymous namespace