avoid hardcoding paths to subdirectories #5
Description
ARCHITECTURES is now a hardcoded list of subdirectories
Not only will the list of subdirectories change soon (for example when we add support for amd/zen5 and aarch/aws/graviton4 to EESSI 2025.06), but some subdirectories may also not appear anymore in future EESSI versions.
Subdirectories should be discovered rather than hardcoded: paths should be determined by looking 2-3 levels deep under software/ for directories that contain both software and modules/all (and optionally accel).