Dear Maintainers,

OpenBoard can use the system virtual keyboard, or can provide its own
virtual keyboard implementation. By default, the system virtual keyboard
is selected in the preferences. It is also written that the system
virtual keyboard should be preferred over the internal one.

However, when system keyboard is chosen, OpenBoard only tries to launch
the virtual keyboard named OnBoard (correct me if I am wrong), and fails
without any error message if it is not installed.

To provide a better user experience by default, I suggest either that:
- openboard package recommends onboard package
- openboard is configured by default to use the internal virtual keyboard

I admit that none of these option is perfect:
- OnBoard has important bugs (at least I faced some) and does not seem
to be really maintained by upstream.
- the internal keyboard does not work when outside of OpenBoard

Anyway, I think any of the above suggestion would be better than the
current situation.

Regards,
Yvan