move folders and templates to other folders

new endpoints:
/services/<service_id>/move-to-folder
/services/<service_id>/move-to-folder/<target_template_folder_id>

* takes in a dict containing lists of `templates` and `folders` uuids.
* sets parent of templates and folders to the folder specified in the
  URL. Or None, if there was no id specified.
* if any template or folder has a differen service id, then the whole
  update fails
* if any folder is an ancestor of the target folder, then the whole
  update fails (as that would cause a cyclical folder structure).
* the whole function is wrapped in a single `transactional` decorator,
  so in case of error nothing will be saved.

app/template_folder/template_folder_schema.py

@@ -1,4 +1,4 @@
-from app.schema_validation.definitions import nullable_uuid
+from app.schema_validation.definitions import nullable_uuid, uuid
 
 post_create_template_folder_schema = {
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -20,3 +20,14 @@ post_rename_template_folder_schema = {
     },
     "required": ["name"]
 }
+
+post_move_template_folder_schema = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "POST schema for renaming template_folder",
+    "type": "object",
+    "properties": {
+        "templates": {"type": "array", "items": uuid},
+        "folders": {"type": "array", "items": uuid},
+    },
+    "required": ["templates", "folders"]
+}