Add join concatenation parameter distinction

[d33bs]

Description

This PR enables "joined" CytoTable output which is not concatenated, reducing the amount of processing involved if a user would like to leverage Parquet datasets (multi-file Parquet tables).

Thank you for any thoughts or feedback you may have!

CC @MikeLippincott

Closes #178

What is the nature of your change?

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

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