Factor YAML manifest manipulation out of the Environment class (#36927)

Change the signature of the Environment.__init__ method to have
a single argument, i.e. the directory where the environment manifest 
is located. Initializing that directory is now delegated to a function 
taking care of all the error handling upfront. Environment objects 
require a "spack.yaml" to be available to be constructed.

Add a class to manage the environment manifest file. The environment 
now delegates to an attribute of that class the responsibility of keeping
track of changes modifying the manifest. This allows simplifying the 
updates of the manifest file, and helps keeping in sync the spec lists in
memory with the spack.yaml on disk.

0 files changed, 0 insertions, 0 deletions