Feature Request: ability to update Materialize workflow with new reference tables

[wiebeytec]

Feature Description

With Vitess 21, one can do:

./vtctldclient Materialize create \
  --workflow "copy_reference_tables" \
  --target-keyspace "$keyspace" \
  --source-keyspace "$source_keyspace" \
  --reference-tables "table1,table2,table3"

(or one can use the Vitess 20 and older method --table-settings <json>)

This uses one VStreams for all reference tables.

It would be great to be able to modify/update this workflow and add tables to it.

Use Case(s)

Use case in short: save load by not adding VStreams per newly created reference tables.

When developers make new tables that need to be present as reference tables, each extra (group of) table(s) adds a VStream. Especially if the source keyspace gets many changes, this can add considirable load. Being able to prevent this would be great.