Include Bus Number in itineraries (Lisbon)

[zecamigo]

Acknowledgments
Please check the following boxes with an x if they apply:

• The feature I want to propose would be useful for the majority of users, not only for me personally.
• I am aware that Transportr is mostly developed by one person in their unpaid spare time.
• I can help myself to get this feature implemented or know someone who wants to do it.

Is your feature request related to a problem? Please describe.

It's hard to figure out what bus you should take just based on it's destination. If there are multiple buses to the same destination it could also set you off track.

Describe the solution you'd like
It would be nice, if available, if the bus number could be displayed in the itinerary.

Describe alternatives you've considered
OSMand has this feature, so I guess an API is available.

Thank you!

[Altonss]

Portugal network had to be removed (see #877) unfortunately, so this issue won't be fixed :/