[Feature] explicitly list out all columns for snowflake's `insert_overwrite` strategy instead of using `*`

[graciegoheen]

Describe the feature

For the insert_overwrite strategy in snowflake, the macro currently uses SELECT * (when no overwrite_columns are provided) instead of explicitly listing all columns (as done in other strategies).

Proposal: generate SQL with an explicit column list instead of SELECT *

This would add a small amount of overhead (i.e. we need to make a call to get the columns).

Additional Context

internal slack thread