Modify odbcDataType.Snowflake to better reflect Snowflake Data Type…

[meztez]

…s documentation

https://docs.snowflake.com/en/sql-reference/data-types

When choosing the maximum length for a VARCHAR column, consider the following:

• Storage: A column consumes storage for only the amount of actual data stored. For example, a 1-character string in a VARCHAR(16777216) column only consumes a single character.

• Performance: There is no performance difference between using the full-length VARCHAR declaration VARCHAR(16777216) and a smaller length.

Since it is used to create tables in Snowflake, I do no see why (from above) it should be limited to 255.

Limiting it can introduce truncation bugs on the user end.

I am a firm believer in preventing end user potential bugs.

[detule]

Thank you!