Introduce "QtPositioning 5.4" QML import tag

5.2 declaration is no longer needed as it is implicitly done by 5.3/5.4.
The 5.4 declaration is just a redeclaration to introduce 5.4. If a
new type is introduced or an existing type changed it can be removed in
favor of the changed type.

Change-Id: I2113751faff062feaa2f7ea5e3ab9f290e90f0c2
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>