[COPY FROM s3] SS-62 Initial support for parquet files

[patrickwwbutler]

This adds initial support and testing for copying from parquet files into tables using COPY INTO ... FROM ... (FORMAT PARQUET).

Also adds WIP user docs for COPY FROM, to be expanded upon.

Motivation

https://linear.app/materializeinc/issue/SS-62/initial-implementation-for-parquet

Tips for reviewers

This is stacked on #34862, so until that is merged, this PR will also include the changes from there. You may wish to wait for that to be merged.

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.