Utils: Further split StringAspect and FilePathAspect

... by introducing "proper" FilePathAspect::value() (and therefore
hiding the inherited StringAspect::value(() and a temporary stringValue()
for the transition period for the remaining users of the QString value.

Change-Id: I40cf4238a09a9009cda0decba1acac82bd730233
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/libs/utils/aspects.cpp

@@ -1327,6 +1327,21 @@ FilePathAspect::FilePathAspect(AspectContainer *container)
     setDisplayStyle(PathChooserDisplay);
 }
 
+FilePath FilePathAspect::operator()() const
+{
+    return filePath();
+}
+
+FilePath FilePathAspect::value() const
+{
+    return filePath();
+}
+
+QString FilePathAspect::stringValue() const
+{
+    return StringAspect::value();
+}
+
 /*!
     Sets the value of this file path aspect to \a value.