Add Option to Name POI

[wp99cp]

We should add an option to name POI. Currently, the name is automatically generated during export; there is now way to change the name on the map, however, the walk-time table can be edited.

[carlobeltrame]

This would have been very valuable in a course of ours. The generated point names are relatively good, considering they are auto-generated. But we try to teach people to manually check and improve the generated walk time table, especially the point names. The coordinate names are very tedious to read. The names of streets are not evident on the swisstopo maps in the PDF, and in many cases they don't uniquely identify a location on the map.

As a workaround, we had to fall back to using the schweizmobil PDFs and labeling any points manually (by editing the PDF), or manually drawing the route on physical swisstopo maps using pencil. So effectively, the generated map was not usable for many of our groups.

As a quick fix, it would already help if the point labels could be optionally omitted on the map. Then, users could manually add relevant labels where they wish using a PDF editor.

[wp99cp]

That's for pointing out the quick fix. We discussed this option at some point and then discarded it. But I think it makes sense if we implement it. It shouldn't be a big deal.

[wp99cp]

b10557d implements an option to hide the description of the points in the exported map