Got EVLA CMS restores working via casa_envoy, using casa_restorepipescript.py when it exists

Restores have been manually tested both with a PPR in the arguments (but no piperestorescript in the cal tar) and without one (with a piperestorescript in the cal tar). No other use-cases of casa_envoy have been manually tested.

To test restores with piperestorescript:

1. Copy the following from /lustre/aoc/cluster/pipeline/dsoc-dev/workspaces/skagan_testing/test_data/with_piperestorescript_2 into your own testing directory:
   1. rawdata/
   2. metadata.json
2. Add empty products and working directories
3. Remove rawdata/products
4. Call /lustre/aoc/cluster/pipeline/dsoc-dev/workspaces/skagan_testing/skagan-casa_envoy3 --restore metadata.json

Without piperestorescript (differences bolded):

1. Copy the following from /lustre/aoc/cluster/pipeline/dsoc-dev/workspaces/skagan_testing/test_data/sans_piperestorescript_with_ppr_in_args into your own testing directory:
   1. rawdata/
   2. metadata.json
   3. PPR.xml
2. Add empty products and working directories
3. Remove rawdata/products
4. Call /lustre/aoc/cluster/pipeline/dsoc-dev/workspaces/skagan_testing/skagan-casa_envoy3 --restore metadata.json PPR.xml

apps/cli/executables/pexable/casa_envoy/casa_envoy/palaver.py

@@ -56,7 +56,8 @@ def _get_settings(cwd: pathlib.Path, args: list) -> dict:
     processing_dir = str(cwd.name)
 
     metadata = args[0]
-    ppr = args[1]
+    # Restores don't always come with a PPR from the arguments, sometimes they want to use the PPR in the cal.
+    ppr = args[1] if len(args) > 1 else None
 
     return {
         "useCasa": use_casa,
@@ -78,25 +79,38 @@ def _setup_launcher(path: pathlib.Path, args: argparse.Namespace) -> LauncherIF:
     :param args: arguments specifying type of processing requested
     :return: Launcher
     """
+    if not (
+        (args.standard_cal is not None)
+        ^ (args.vlass_cal is not None)
+        ^ (args.standard_img is not None)
+        ^ (args.vlass_img is not None)
+        ^ (args.restore is not None)
+        ^ (args.split is not None)
+    ):
+        raise ValueError(
+            "Expected exactly one of standard_cal, vlass_cal, standard_img, vlass_img, or restore arguments to be provided, found none or multiple"
+        )
     parameters = {}
 
     if args.parallel is not None:
         parameters["requested_parallel"] = args.parallel
 
-    if args.standard_cal is not None or args.vlass_cal is not None:
+    if args.standard_cal is not None or args.vlass_cal is not None or args.restore is not None:
         if args.standard_cal:
             parameters = {**parameters, **_get_settings(path, args.standard_cal)}
-            if args.restore:
-                parameters["product_type"] = ProductType.RESTORE.value
-            else:
-                parameters["product_type"] = ProductType.STD_CAL.value
-
-        if args.vlass_cal:
+            parameters["product_type"] = ProductType.STD_CAL.value
+        elif args.vlass_cal:
             parameters = {
                 **parameters,
                 **_get_settings(path, args.vlass_cal),
                 "product_type": ProductType.VLASS_CAL.value,
             }
+        elif args.restore:
+            parameters = {
+                **parameters,
+                **_get_settings(path, args.restore),
+                "product_type": ProductType.RESTORE.value,
+            }
 
         return CalibrationLauncher(parameters)
     elif args.standard_img is not None or args.vlass_img is not None:
@@ -175,9 +189,10 @@ def arg_parser() -> argparse.ArgumentParser:
     )
     parser.add_argument(
         "--restore",
+        nargs="+",
         required=False,
-        action="store_true",
-        help="run the restore measurement set CASA pipeline, use in conjunction with '-c'",
+        action="store",
+        help="run the restore measurement set CASA pipeline",
     )
     parser.add_argument(
         "--integrated",