[Parquet-raster] Definition of Geo-referencing information

[jiayuasu]

          +1. 

We may also want to consider aligning with STAC, see https://github.com/stac-extensions/projection - we just define shape and transform instead of the col, x, etc. Planet's data api did things that way, and the stac way felt like an improvement.

Originally posted by @cholmes in #259 (comment)

[migurski]

I’m unfamiliar with the STAC way but it doesn’t look incompatible. My only objection would be to the 3x3 matrix with the optional third row always [0, 0, 1] — I understand why that third row is needed when chaining homogenous affine transformations but why store it?

[jiayuasu]

This might be related to #266