Add LTR/RTL layout changes support for the internationalisation of Neptune UI

As a next step for better internationalisation support, Neptune UI should support a LTR/RTL layout changes. No restart of the UI should be required to switch between LTR/RTL.

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Some history FYI from the original task. The below results in multiple tasks which will be cloned from the original one:

Based on the discussion with Alistair and Alex at TU Detroit (June 2016), modified based on workshop at Berlin September 2016.

For demoing Qt's i18n features it would be nice if Neptune could do live language changes and LTR/RTL layout changes.

• Need setting for the system language. Is this an OS setting or is there a separate UI setting taking into account whether on target or on PC development?
• On System language change need to notify all the apps.
• QML needs to be enhanced to have proper fix for language change. Volker has a patch that was rejected. Simon knows this is a problem and says that changes coming that makes this easier.
• To make the notification propagation work we need an IPC mechanism.

A demo app has been built that is a starting point for demonstrating this feature. It does make the VKB follow the system language rather than having it's own inconvenient to use language cycle button. This feature should though be built into the system UI or an system settings app.