legacy: REST API legacy fixes

* Fixes issue with legacy API where it was allowed to sent a FP7
  project identifier as a single number.

* Fixes issue with legacy API where a single alternate identifier was
  not correctly handled.

site/zenodo_rdm/config.py

@@ -331,3 +331,13 @@ def lock_edit_record_published_files(record):
 
 RDM_LOCK_EDIT_PUBLISHED_FILES = lock_edit_record_published_files
 """Lock editing already published files (enforce record versioning)."""
+
+APP_RDM_RECORD_THUMBNAIL_SIZES = [
+    "10",
+    "50",
+    "100",
+    "250",
+    "750",
+    "1200",
+]
+"""Thumbnail sizes."""

site/zenodo_rdm/legacy/deserializers/metadata.py

@@ -134,11 +134,14 @@ def split_identifiers(self, data, **kwargs):
             else:
                 related_identifiers.append(identifier)
 
-        if related_identifiers:
-            data["related_identifiers"] = related_identifiers
+        # A single alternate identifier will need ot set
+        if input_identifiers:
+            if related_identifiers:
+                data["related_identifiers"] = related_identifiers
+            else:
+                data.pop("related_identifiers")
         if alternate_identifiers:
             data["alternate_identifiers"] = alternate_identifiers
-
         return data
 
     title = SanitizedUnicode()
@@ -182,6 +185,10 @@ def load_funding(self, obj):
             return missing
 
         for grant in grants:
+            # FP7 project grant - special case for FP7 project grant
+            if not "::" in grant["id"]:
+                grant["id"] = "10.13039/501100000780::{0}".format(grant["id"])
+
             # format "10.13039/501100000780::190101904"
             id_parts = grant["id"].split("::", 1)
             assert len(id_parts) == 2