Update api docs with usage examples and responses

dev-manual/api/api-reference-archivematica.rst

@@ -491,6 +491,38 @@ Response definitions:
 ==================   ==========================================================
 
 
+Usage example (assuming that avalon.csv exists)::
+
+  curl -X POST \
+  http://my_archivematica_instance.archivematica.org/api/ingest/copy_metadata_files/ \
+  -H 'Authorization: ApiKey [_your_username_]:[_your_ApiKey_]' \
+  -H 'Content-Type: application/x-www-form-urlencoded' \
+  -d 'sip_uuid=a7f1f36c-55c1-4fb7-a898-76d102e847dc&source_paths%5B%5D='''NmRjYTgxNDAtMDg2NC00MzE5LTg2ZDctNTg0ZjZiZTY4N2EzOi9ob21lL2FyY2hpdmVtYXRpY2EvYXJjaGl2ZW1hdGljYS1zYW1wbGVkYXRhL2lzc3VlX3RlbXBsYXRlLm1k''''
+
+
+Response examples
+
+200 OK::
+
+    {
+      "error": false,
+      "message": "Metadata files added successfully."
+    }
+
+400 Bad Request ::
+
+    {
+      "error": true,
+      "message": "sip_uuid and source_paths[] both required."
+    }
+
+500 Internal Server Error::
+
+    {
+      "error": true,
+      "message": "sip_uuid and source_paths[] both required."
+    }
+
 .. _admin-resource:
 
 Administration