Add UI controls by hardware keys in the cluster UI

As a user, I want to have a navigation support for the UI. Currently the Neptune UI is a touch-only HMI. We still use a few keyboard shortcuts for development purposes. Some of those, like switching the content shown on cluster, are actually HMI actions and should be mapped to an actual device. The idea is to add support of a steering wheel used in games and use it in shows. A use of a standard PC keyboard should be retained for cases when no steering wheel is connected.

The following use cases have been identified for the initial implementation:

1. Use key on the wheel to switch the content in the center of the cluster UI between apps using this area (currently Maps and Media)
2. Be able to emulate right and left turn by another set of keys
3. Go forward and backward with arrow keys through the songs played by the Media Player
4. Document all used keys, which hardware is required, and how it is implemented in the UI code in a dedicated page of the docs, not just in the Overview page (https://doc-snapshots.qt.io/neptune3ui/neptune3ui-overview.html)