Table Identification Template - Fix Dead Link

## Why are we implementing it?

Improve user experience, provide template indicated to exist in documentation.

## What is the issue?

In the `migration_mt_schema` there is a recommendation: "We typically advise tracking this with a spreadsheet, and have created a [template](https://docs.google.com/spreadsheets/d/1jYlc22lHdP91pTrb6s35QfrN9nTE1BkVJnCSZeQ7ZmI/edit) you can use."

The issue is this spreadsheet does not exist, at least at this link, any longer.

If this template still exists updating this link and restoring access would be helpful!