> guix: Unify fetch methods
> guix: Drop unneeded modules
> guix: Specify symbols in modules explicitly
>
> This change improves the maintainability of the manifest:
> (1) It allows to remove the module when the specified symbols are no
> longer used.
> (2) It prevents accidental use of other symbols, such as `bash`
> instead of `bash-minimal`.
This is a backport of core#27811
Depends on D15344