Add SQLite mixed-type data handling capabilities

[d33bs]

Description

This change seeks to address #38 through dynamic handling of mixed-type SQLite column data when exceptions of this kind are encountered with DuckDB SQLite queries.

When mixed type exceptions are encountered, the design intent here strives to keep as much data as possible while assuming one or many values of mismatching type within the SQLite table being queried. SQLite3 SQL case statements are formed to convert mismatched storage class values to NULL's for every column in the table being queried. These SQLite NULL's are interpreted by sqlite3 as Python None's, which are then interpreted as pyarrow.null()'s for export to Parquet.

For SQLite data sources where mixed typing exceptions are not encountered, the default capabilities through DuckDB function as usual.

What is the nature of your change?

• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• This change requires a documentation update.

Checklist

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[falquaddoomi]

Looking good; I left a couple of comments. Cool to see you making the tool more robust.

[gwaybio]

@falquaddoomi @d33bs - is this ready to merge? Will it solve #38? (@jenna-tomkinson and @MattsonCam are currently blocked by it for the JUMP single cell analysis)

[gwaybio]

Update, @d33bs - just saw your comment in #38 (comment)

[gwaybio]

LGTM! Excited to get this merged in.