Add option to draw streets (as orientation for pole and grid positioning) in "consumer selection" page

[KatLamm]

In case there are no streets recognised by the map/layer, user can get the oportunity to show the tool the route of streets where poles an grid lines should be positioned.

Ideally: "When no streets are recognized, show a message with an option to “Draw streets manually”.

Integrate a simple draw function that lets the user sketch routes on the map (consumer selection page)

Poles and grid lines should then be positioned along these manually drawn routes, following the same logic as with automatically recognized streets.

[paulapreuss]

Road fetching from the Overpass API already being implemented by @CelinaKellinghaus, as well as approaches for selecting the roads and using them for pole orientation. Maybe this feature in combination with the pole editing feature being implemented for OGP Mozambique might be enough, so that manually drawing streets would not be needed.

[paulapreuss]

@CelinaKellinghaus let's merge the roads feature into this repository and leave it out of the OGP Nigeria for now. In a next step, we can implement selecting the roads from the map to use them as guides for the poles, which will require some changes to the optimizer-offgridplanner