Consolidate Spack's internal filepath logic to a select
few places and refactor to consistent internal useage of
os.path utilities. Creates a prefix, and a series of utilities
in the path utility module that facilitate handling paths
in a platform agnostic manner.
Convert Windows paths to posix paths internally
Prefer posixpath.join instead of os.path.join
Updated util/ directory to account for Windows integration
Co-authored-by: Stephen Crowell <stephen.crowell@khq.kitware.com>
Co-authored-by: John Parent <john.parent@kitware.com>
Module template format for windows (#23041)