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

@@ -690,7 +690,7 @@ def get_release_info(mpsd_release: str, root_dir: Path) -> Tuple[str, str, List[
     Get information about the specified release.
 
     Get information about the specified release, such as the branch and commit hash
-    of the Spack environments repository and the available toolchains.
+    of the Spack environments repository and the available package_sets.
 
     Parameters
     ----------
@@ -705,8 +705,8 @@ def get_release_info(mpsd_release: str, root_dir: Path) -> Tuple[str, str, List[
         The name of the branch for the Spack environments repository.
     spe_commit_hash : str
         The commit hash for the Spack environments repository.
-    available_toolchains : list
-        A list of strings representing the available toolchains for the release.
+    available_package_sets : list
+        A list of strings representing the available package_sets for the release.
 
     Raises
     ------
@@ -738,8 +738,8 @@ def get_release_info(mpsd_release: str, root_dir: Path) -> Tuple[str, str, List[
                 .stdout.decode()
                 .strip()
             )
-            available_toolchains = os.listdir("toolchains")
-    return spe_branch, spe_commit_hash, available_toolchains
+            available_package_sets = os.listdir("toolchains")
+    return spe_branch, spe_commit_hash, available_package_sets
 
 
 def prepare_environment(mpsd_release: str, root_dir: Path) -> List[str]:
@@ -749,7 +749,7 @@ def prepare_environment(mpsd_release: str, root_dir: Path) -> List[str]:
     It does the following steps:
     Clones the spack-environments repository.
     Determines the branch and commit hash of the spack-environments repository
-    and the available toolchains.
+    and the available package_sets.
     Logs the command usage.
 
     Parameters
@@ -762,8 +762,8 @@ def prepare_environment(mpsd_release: str, root_dir: Path) -> List[str]:
 
     Returns
     -------
-    available_toolchains : list
-        A list of available toolchains for the given MPSD release.
+    available_package_sets : list
+        A list of available package_sets for the given MPSD release.
 
     Example
     -------
@@ -799,13 +799,13 @@ def prepare_environment(mpsd_release: str, root_dir: Path) -> List[str]:
         f"Release {mpsd_release} is prepared in {release_base_dir}"
     )
 
-    spe_branch, spe_commit_hash, available_toolchains = get_release_info(
+    spe_branch, spe_commit_hash, available_package_sets = get_release_info(
         mpsd_release, root_dir
     )
     record_script_execution_summary(
         mpsd_release, root_dir, spe_branch=spe_branch, spe_commit_hash=spe_commit_hash
     )
-    return available_toolchains
+    return available_package_sets
 
 
 def get_native_microarchitecture():