(core) Add PUT /records DocApi endpoint to AddOrUpdate records

Summary:
As designed in https://grist.quip.com/fZSrAnJKgO5j/Add-or-Update-Records-API

Current `POST /records` adds records, and `PATCH /records` updates them by row ID. This adds `PUT /records` to 'upsert' records, applying the AddOrUpdate user action. PUT was chosen because it's idempotent. Using a separate method (instead of inferring based on the request body) also cleanly separates validation, documentation, etc.

The name `require` for the new property was suggested by Paul because `where` isn't very clear when adding records.

Test Plan: New DocApi tests

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3251

sandbox/grist/table.py

@@ -443,6 +443,10 @@ class Table(object):
         # the marker is moved to col_id so that the LookupMapColumn knows how to
         # update its index correctly for that column.
         col_id = lookup._Contains(col_id)
+      else:
+        col = self.get_column(col_id)
+        # Convert `value` to the correct type of rich value for that column
+        value = col._convert_raw_value(col.convert(value))
       key.append(value)
       col_ids.append(col_id)
     col_ids = tuple(col_ids)