feat: add multi-join expression support

[agavra]

fixes #5062

Description

This change uses the JoinTree to track the equivalence of the join criteria across the different join stages, then uses that information to decide whether or not a repartition is necessary. This opens the door to using different expressions (and non-matching expressions) on different parts of the join.

Testing done

• unit testing
• QTT tests

Reviewer checklist

• Ensure docs are updated if necessary. (eg. if a user visible feature is being added or changed).
• Ensure relevant issues are linked (description should include text like "Fixes #")

[vpapavas]

LGTM, thank you @agavra! We discussed offline but just writing it here so that it doesn't get lost: In absence of join ordering and multi-key partitioning, the approach has the downside of creating inefficient partitioning strategies where at different levels we partition on the same keys and create duplicate work. But given the current limitation, the approach is good enough and gets the job done.