To allow generating a bank snapshot directory with full state information, we need to
hardlink account appendvec files from the runtime operation directory to a snapshot
hardlink directory. This is to create the run/ and snapshot sub directories for an
account_path provided by the user. These two sub directories are on the same file
system partition to allow hard-linking.
For all account_paths, create the run/ and snapshot/ sub directories.
If an account_path directory does not exist, create it.
It returns (account_run_paths, account_snapshot_paths) or error
Creates directories if they do not exist, and canonicalizes the paths.
Delete the files and subdirectories in a directory.
This is useful if the process does not have permission
to delete the top level directory it might be able to
delete the contents of that directory.