Allow the order of paths to be determined

[p-p-s]

Is your feature request related to a problem? Please describe.
When adding a path to the map, it appears in that very editing session that the last added path is placed on top of the other paths added before. But when closing the editing session and then viewing the map in a new session, paths are being placed in lexical order of their names. This is misleading editors as they only late realize that they are not getting what they thought they would get. And it is also not intuitive what the workaround would be (renaming their GPX paths to define the intended order on the map).

My example
At https://umap.openstreetmap.fr/en/map/makalu-base-camp-trek_1112563#13/27.6178/87.2857 activate the Customization options layer and see the dashed grey foot path partially sharing the way with the brown 4WD dirt road. The dashed path must be placed on top of the solid path to make both visible in the shared parts. In my case, Chiuribas - Gola (4WD) was finally placed on top of Chiuribas - Gola, although I deleted Chiuribas - Gola to add it again and it appeared on top in the editing session. The Holy Spirit told me the other day that the solution could be renaming Chiuribas - Gola into Chiuribas - Gola (walk), so that lexically it would appear after Chiuribas - Gola (4WD) and therefore be loaded after Chiuribas - Gola (4WD) to appear on top.

Describe the solution you'd like

1. Allow the order of paths within a layer to be determined independently of their name, like the "Drag to reorder" control works on the Manage layers pane.
2. When a new path is added by the editor, show it right a way in the final order on top of one another.
3. Should 2. not be possible, more than one path is added and some paths overlap in parts, warn the user of the overlap and that the final order could be different
4. Whether 2. or 3., give the editor a hint how to achieve the intended order. In case 1. would not be possible, hint the the lexical order.