The `sql_database.py` is unnecessarily placed in the root code folder.
A similar code is usually placed in the `utilities/`.
As a byproduct of this placement, the sql_database is [placed on the top
level of classes in the API
Reference](https://api.python.langchain.com/en/latest/api_reference.html#module-langchain.sql_database)
which is confusing and not correct.
- moved the `sql_database.py` from the root code folder to the
`utilities/`
@baskaryan
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Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
