Refactor Spatial Dependencies in AccessMod

[fxi]

We've identified issues affecting AccessMod related to outdated spatial packages:

1. The raster package has been replaced by terra.
2. The rgeos package should be replaced by terra or sf.
3. rgrass now requires the use of terra and sf.
4. The sp package is considered outdated and should be replaced by sf.

Currently, our code forces rgrass to use sp, which is not recommended. Continuing to automate builds with obsolete packages is not sustainable.

Additionally, AccessMod uses proj4, which is also obsolete. We need to transition to WKT projection definitions. I've found alternatives for determining projection units and types during project creation and uploads, but proj4 is still used elsewhere in the codebase.

There are related issues (#437 and #433) that point towards the need for a comprehensive refactor of AccessMod's spatial dependencies.

GRASS GIS Updates:
GRASS has evolved significantly, though I haven't noticed any breaking changes. There is a minor bug fix needed for r.walk, which I can integrate into r.walk.accessmod during the build process.

Action Required:
We need to rethink spatial operations in AccessMod, excluding GRASS. GRASS-related operations should remain mostly unaffected.

More info
https://r-spatial.org/r/2022/04/12/evolution.html
https://geocompx.org/post/2023/rgdal-retirement/index.html
https://github.com/r-spatial/evolution?tab=readme-ov-file
https://github.com/r-spatial/evolution/blob/main/pkgapi_230305_refs.csv