SNOW-782235: Support multi table INSERT clause (`INSERT ALL`)

## What is the current behavior?
There is currently no support

## What is the desired behavior?
Add an `InsertAll` clause, similar to `MergeInto`, etc

## How would this improve `snowflake-connector-python`?
more compatibility with snowflake db features

## References, Other Background
https://docs.snowflake.com/en/sql-reference/sql/insert-multi-table