AY-4801 - new validator for editorial_pckg

Currently checks only by file names and expects flat structure.
It ignores path to resources in otio file as folder might be dragged in and
published from different location than it was created.

client/ayon_core/hosts/traypublisher/plugins/publish/validate_editorial_package.py

@@ -0,0 +1,70 @@
+import os
+import opentimelineio
+
+import pyblish.api
+from ayon_core.pipeline import PublishValidationError
+
+
+class ValidateEditorialPackage(pyblish.api.InstancePlugin):
+    """Checks that published folder contains all resources from otio
+
+    Currently checks only by file names and expects flat structure.
+    It ignores path to resources in otio file as folder might be dragged in and
+    published from different location than it was created.
+    """
+
+    label = "Validate Editorial Package"
+    order = pyblish.api.ValidatorOrder - 0.49
+
+    hosts = ["traypublisher"]
+    families = ["editorial_pckg"]
+
+    def process(self, instance):
+        editorial_pckg_data = instance.data.get("editorial_pckg")
+        if not editorial_pckg_data:
+            raise PublishValidationError(
+                f"Editorial package not collected")
+
+        folder_path = editorial_pckg_data["folder_path"]
+
+        otio_path = editorial_pckg_data["otio_path"]
+        if not otio_path:
+            raise PublishValidationError(
+                f"Folder {folder_path} missing otio file")
+
+        resource_paths = editorial_pckg_data["resource_paths"]
+
+        resource_file_names = {os.path.basename(path)
+                               for path in resource_paths}
+
+        otio_data = opentimelineio.adapters.read_from_file(otio_path)
+
+        target_urls = self._get_all_target_urls(otio_data)
+        missing_files = set()
+        for target_url in target_urls:
+            target_basename = os.path.basename(target_url)
+            if target_basename not in resource_file_names:
+                missing_files.add(target_basename)
+
+        if missing_files:
+            raise PublishValidationError("Otio file contains missing files "
+                                         f"'{missing_files}'.")
+
+        instance.data["editorial_pckg"]["otio_data"] = otio_data
+
+    def _get_all_target_urls(self, otio_data):
+        target_urls = []
+
+        # Iterate through tracks, clips, or other elements
+        for track in otio_data.tracks:
+            for clip in track:
+                # Check if the clip has a media reference
+                if clip.media_reference is not None:
+                    # Access the target_url from the media reference
+                    target_url = clip.media_reference.target_url
+                    if target_url:
+                        target_urls.append(target_url)
+
+        return target_urls
+
+