Whitelist for stations/trains

[The-Shortman]

Is your feature request related to a problem? Please describe.
For large public servers using this mod, it might be more useful to include a train/station 'whitelist' so that only public transport services can be listed in the Navigator, as a lot of other players will, more than likely, frequently utilise their own automated trains on public railways, and new stations will regularly appear on the charts that clutter the search interface.

Describe the solution you'd like
An option to 'whitelist' certain train/station groups in the Navigator, as an alternative to the already existing 'blacklist' option.