(core) Allow using negative rowIds to add records and refer to them in Reference values.

Summary:
- When adding records, negative rowIds may now be specified. They'll be replaced by proper IDs.
- If these negative IDs are used in Reference columns in subsequent actions in
  the same bundle of UserActions, they get replaced with the proper rowIds.
- Use this to sync ACLResources and ACLRules from UI in a single batch of UserActions.
- Resolve the TODOs in GranularAccess test, to no longer need to guess resource rowIds.

Test Plan: Added a python unittest for mapping IDs; updated browser tests.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2691

sandbox/grist/engine.py

@@ -862,7 +862,8 @@ class Engine(object):
 
       # If there are values for any PositionNumber columns, ensure PositionNumbers are ordered as
       # intended but are all unique, which may require updating other positions.
-      nvalues, adjustments = col_obj.prepare_new_values(values)
+      nvalues, adjustments = col_obj.prepare_new_values(values,
+          action_summary=self.out_actions.summary)
       if adjustments:
         extra_actions.append(actions.BulkUpdateRecord(
           action.table_id, [r for r,v in adjustments], {col_id: [v for r,v in adjustments]}))
@@ -880,7 +881,8 @@ class Engine(object):
         defaults = [col_obj.getdefault() for r in row_ids]
         # We use defaults to get new values or adjustments. If we are replacing data, we'll make
         # the adjustments without regard to the existing data.
-        nvalues, adjustments = col_obj.prepare_new_values(defaults, ignore_data=ignore_data)
+        nvalues, adjustments = col_obj.prepare_new_values(defaults, ignore_data=ignore_data,
+            action_summary=self.out_actions.summary)
         if adjustments:
           extra_actions.append(actions.BulkUpdateRecord(
             action.table_id, [r for r,v in adjustments], {col_id: [v for r,v in adjustments]}))