Tracker: Use SPDX license headers

[ibgreen]

To align with OpenJS foundation recommendations.

Review each source file and make sure the SPDX clause reflects all licenses

• 3d-tiles
• arrow
• bson
• compression
• copc
• core
• crypto
• csv
• draco
• excel
• flatgeobuf
• geopackage
• geotiff
• gis
• gltf
• i3s
• images
• json
• kml
• las
• lerc
• loader-utils
• math
• mvt
• netcdf
• obj
• parquet
• pcd
• ply
• pmtiles
• polyfills
• potree
• schema
• shapefile
• terrain
• textures
• tile-converter
• tiles
• video
• wkt
• wms
• worker-utils
• xml
• zarr
• zip

[ibgreen]

@chrisgervang

[chrisgervang]

What do you think of adding the kepler script to vis.gl projects? I suppose that only works if its a consistent SPDX header. It'd be helpful for projects with one header throughout.