Add a way for duckdb users to build parquet files instead of tables

[mtoy-googly-moogly]

the CREATE TABLE $(nam) AS SELECT pattern in the build command doesn't allow duckdb users to maintain their persistant objects as parquest file

#@ persist name="tableName" { duckdb = "differnet stuff" }

or something like that to allow the building of parquet files when this model is used with a duckdb connection

[mtoy-googly-moogly]

COPY (SELECT * FROM my_table) 
TO 'output.parquet' 
(FORMAT PARQUET, OVERWRITE TRUE);

I wonder if a general extension to allow the builder-user to write the SQL themselves, in the config file

builderCommands: {
  duckdb: {
    createAndReplace: "COPY (SELECT * FROM $SQL) TO '$TABLE' (FORMAT PARQUET, OVERWRITE TRUE);"
  }
}

Except the $ gesture should allow substitution from the tags on the persist line