Add the ability to re-project the images within the pipeline.

[andrewphilipsmith]

Requirement:

• The pipeline should be able to re-project the image to a user-specified CRS.
• Typically, this will occur (i) after the composite image has been created and (ii) before it is cut into chips? Though this should be configurable.
• For the UrbanGrammar context, the target CRS is British National Grid (https://epsg.io/27700)

To check:

• [x] Confirm how the downloader code specifies the CRS (either implicitly or explicitly) to GEE. (See https://developers.google.com/earth-engine/guides/projections for details)
• [ ] Test whether or not downstream modules work with projected coordinates.
• [ ] Can the pipeline work with a mixture of data in one CRS and pipeline-level metadata in a different CRS (e.g. the images are stored and analysed in BNG, but the bounds are in Lon/Lat)?

Questions:

• [ ] In terms of code quality, is it acceptable for code to use the variable names longitude, and latitude even if (i) they are sometimes referring to eastings and northings and (ii) the code works correctly in practice.

References:

• https://urbangrammarai.xyz/data_processing/code/GHS-composite-S2_mirror.html
• https://github.com/urbangrammarai/data_processing/blob/0e36f7e8fa2a49b8ceb7365f646b8199d6478103/utils/__init__.py#L185

[andrewphilipsmith]

I recommend that we close #21 for the reasons given here https://github.com/urbangrammarai/gee_pipeline/pull/21#issuecomment-1204947779. #23 satisfies one of the checks listed above, but not all of them.

However, we should keep this issue open until we have completed #6 and can assess the use of BNG throughout the entire pipeline.