Split ways on crossing points

To fix mapping errors like this where the sidewalk stops but the road is not split, it would be great to have a simple split option in the editor.
The parking lane editor https://zlant.github.io/parking-lanes/#18.19/52.747057/13.240385 had a similar feature where one could select a scissors icon and then all intersections showed the icon so I could click it to split the way.

However, there needs to be some checks to handle relations, which ATM every editor has to implement themselves. See also https://github.com/rapideditor/rapid-sdk/issues/165
The code from zlant and iD and MapComplete should have checks that can be reused.

Examples: Route relations can just be copied. But the order are an issue. But other relations like turn restrictions should not be copied.

The easiest is to just disallow splitting when there are relations.