Rename QtSupport::BaseQtVersion to QtVersion

... and the Utils::QtVersion enum to Utils::QtMajorVersion to avoid
conflicts.

Change-Id: Ib688c67388272b7204a91444155f60b8c18a56bd
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/tools/sdktool/addqtoperation.cpp

@@ -43,7 +43,7 @@ using namespace Utils;
 const char PREFIX[] = "QtVersion.";
 const char VERSION[] = "Version";
 
-// BaseQtVersion:
+// QtVersion:
 const char ID[] = "Id";
 const char DISPLAYNAME[] = "Name";
 const char AUTODETECTED[] = "isAutodetected";