Toolchain becomes package set part2

This is mostly a search and replace exercise (and thus probably correct). (Individual commits deal with kind-of single functions, and their associated tests.)

More complicated changes I have tried to move into separate merge requests.

mpsd-software.py

@@ -930,7 +930,8 @@ def install_environment(
 
     for package_set in package_sets:
         if package_set not in available_package_sets:
-            msg = f"Package_Set '{package_set}' is not available in release {mpsd_release}."
+            msg = f"Package_Set '{package_set}' is not available"
+            msg += f" in release {mpsd_release}. "
             msg += "Use 'available' command to see list of available package_sets."
             logging.error(msg)
             sys.exit(1)
@@ -966,7 +967,8 @@ def install_environment(
                 ),
             )
             run(
-                f"bash {spack_setup_script} {' '.join(install_flags)} {package_set} 2>&1 "
+                f"bash {spack_setup_script} "
+                f"{' '.join(install_flags)} {package_set} 2>&1 "
                 f"| tee -a {build_log_path} ",
                 shell=True,
                 check=True,
@@ -975,7 +977,9 @@ def install_environment(
 
 def remove_environment(release, package_sets, target_dir):
     """Remove release from installation."""
-    msg = f"Removing release {release} with package_sets {package_sets} from {target_dir}"
+    msg = (
+        f"Removing release {release} with package_sets {package_sets} from {target_dir}"
+    )
     logging.info(msg)
     raise NotImplementedError(msg)