Reduce bundle size

[cmahnke]

Currently the bundle is quite large:

hdr-canvas.cjs                   153 kB
hdr-canvas.cjs.map               343 kB
hdr-canvas.d.ts                  2.45 kB
hdr-canvas.js                    153 kB
hdr-canvas.js.map                343 kB
hdr-canvas.min.js                58.7 kB
hdr-canvas.min.js.map            251 kB

One possible solution is to define colorjs.io as external, another one would be the separation of the detection and the Uint16Image class.