Add icechunk-based Zarr example

[kylebarron]

Using https://github.com/EarthyScience/icechunk-js as a driver to plug into zarrita.js

From @abarciauskas-bgse

NLDAS should be a good dataset to test with deck.gl-raster. I just tested opening + plotting (variable Tair) using the code on the README from my local machine and it worked fine!

[kylebarron]

Also linking existing discussion in NASA-IMPACT/veda-odd#384