Revival ideas

Spurred on by all the progress in Muv, here are some ideas after that cutover PR is merged to revive work on osm2streets.

- [x] Clean up Street Explorer code, likely starting with svelte-maplibre and others from #220
- [x] Display full detail from Muv when clicking a lane or road (play around with some ideas for formatting)
- [ ] Plug semantic gaps, like adding `Direction::Both`
- [ ] Revisit #223, region-specific assumptions for lane widths and also color/styling
- [ ] Revisit the dependency on https://github.com/a-b-street/geom. I've been using georust in newer projects. It could be worth revisiting some of the core LineString offsetting code in `geom` and trying newer approaches
- [ ] Revisit the algorithm that generates vehicle turns in A/B Street. Modernize, remove old assumptions from the traffic simulation days, and get it working in here.
- [x] Focus on footways and crossings, and try to render markings. Don't worry about any overlapping geometry or graph simplification yet.