Add method to plot time-distance diagram

[miguelrelvaspires]

Create, for each service, a function that generates something like the plot below, with marks in the distance (y-axis) for each station of that service. Time (x-axis) would comprise the 24 hours of the day.

[gmatosferreira]

Feasible with https://r-graph-gallery.com/line-plot.html

Per route?

Challenges:

• Add stop name on y axis
• Compute distance between stops (straight line, simplification? we could also use shapes and its length?)