Trying some things with sampling data. Started with just plotting bottom
bathymetry, and a way of sampling along the measuring line. Hopefully
that will make it easy to pull down whatever stats after the fact.
Also, ruined the plotly import (sry @mrtz). Imported Plot through
react-plotly.js directly, which didn't work with the aliasing. Will try
to fix later.
Replaces the `bun2nix` bun.nix generated file with `mkDerivation` containing
the node modules. This should decrease the nix evaluation time and decrease
the bundle size.
Also switches to [lon](https://github.com/nikstur/lon) instead of npins
for pinning nixpkgs, since it uses the nix library directly instead of
shelling out to `nix-shell` or `nix-build`.
