spack-reusable: adapted the workflow for spack-0.22.2

[nicolaslg]

• use of version number 999 no longer worked and returned in error Error: FetchError: Will not fetch gmds@999.
  As not specifying a version number results in error Error: Packages to develop must have a concrete version, now the "preferred version" number is extracted from a call to spack info
• spack-0.22.2's preferred python version is 3.11.7, so the path to site-packages is modified from the previous 3.10 directory