[WIP] Manually merges GeoJSON features to fix buffer

[alulsh]

Ref https://github.com/dcfemtech/hackforgood-waba-map/issues/1

This manually unions the bikelane geojson features but introduces a new performance issue - it takes several minutes to dynamically generate a buffer for 1285+ features.

We should instead consider pregenerating the buffer (perhaps a new buffer geojson file) and loading that from disk instead of dynamically generating it when a user first loads the page.

/cc @khiggins115 @juliekdang

[alulsh]

Closing - stale. Still useful to refer back to this as a reference.