Add factory reset for Settings

[kmcnaught]

Management Console – “reset all settings to default” button – rename user settings file so it is not used, but could be recovered if required.

[kmcnaught]

If some settings are set during installation (e.g. language, eye tracker) we need to think about whether user's expect 'reset to default' to mean 'universal default' or 'installed state'. If the latter, we'll need to make sure installer-specified settings are cached to support this.