Add function to infer schema from files(CSV/Parquet)

[BohuTANG]

Summary

As arrow2 has infer_schema:
Parquet:
https://github.com/jorgecarleitao/arrow2/blob/5725fa3c18830f88ed0ed67067dda5c1d2080dca/src/io/parquet/read/schema/mod.rs#L23-L31

CSV:
https://github.com/jorgecarleitao/arrow2/blob/79b87b629d8fdc3fa40b5ad7abc3889c5102a52b/src/io/csv/read/infer_schema.rs#L15

We can add a function INFER_SCHEMA to do the schema infer, syntax like:

INFER_SCHEMA(
LOCATION => '{ internalStage | externalStage }'
  , FILE_FORMAT => '<format_name>'
)

example(from snow):

select * from infer_schema(location=>'@mystage/geography/cities.parquet' , file_format=>'parquet')


+-------------+---------+----------+---------------------+--------------------------+
| COLUMN_NAME | TYPE    | NULLABLE | EXPRESSION          | FILENAMES                |
|-------------+---------+----------+---------------------+--------------------------|
| continent   | TEXT    | True     | $1:continent::TEXT  | geography/cities.parquet |
| country     | VARIANT | True     | $1:country::VARIANT | geography/cities.parquet |
+-------------+---------+----------+---------------------+--------------------------+

Reference:
https://docs.snowflake.com/en/sql-reference/functions/infer_schema.html

[BohuTANG]

cc @Xuanwo

[Xuanwo]

I'm taking this issue now.

[Xuanwo]

Already implemented by @youngsofun