Move low level details `geos` package into `internal/rawgeos`

[peterstace]

Description

This is to pave the way to allow unification of the GEOS wrapper between the geos cmprefimpl/cmpgeos packages. The idea is that the internal/rawgeos package will (soon) be a dependency of both packages, with the extra wrapped functions that cmpgeos requires (soon) moved from cmpgeos into internal/rawageos.

Check List

Have you:

• Added unit tests? N/A

• Add cmprefimpl tests? (if appropriate?) N/A

• Updated release notes? (if appropriate?) Not yet -- I'll update these once the geos/cmpgeos packages are fully unified.

Related Issue

• https://github.com/peterstace/simplefeatures/issues/531

[peterstace]

Thanks for reviewing @albertteoh 😁