Add gallery example for plotting earthquakes on the profile view

[maxrjones]

Description of the desired feature

This was another request from the AGU workshop, which would make a great gallery example. The request was to plot the earthquakes within 100 km on either side of the line in the profile view.

Are you willing to help implement and maintain this feature?

Maybe

[yvonnefroehlich]

In case the earthquakes should be plotted as beachballs also in the depth sections, we first need to wrap coupe, please see PR #2019.