Add Nominatim to `speedLimit.url` with zoom, as it returns speed limits.

Hi, I'm already using Nominatim for geocoding, and I want to use it for speed limits. I'm not planning to host other providers. Can I do that with Nominatim? I only see examples on the config page about Overpass.

Example : https://nominatim.openstreetmap.org/reverse?format=jsonv2&lat=51.51465608749&lon=-3.1915241864833&zoom=18&addressdetails=1&extratags=1

It's not supported currently, but possible to implement if we know the format.

I think it must be added on geocode level and be saved as an attribute in position
I will create a PR if i found a way to implement it correctly

It has to be done as a separate provider from geocoding.