Allow configuring different readers for DF integration

[AdamGS]

This PR allows using non object-store based readers when working with the Vortex FileSource, like when users want custom caching, observability or anything else.

[codspeed-hq]

Merging this PR will not alter performance

✅ 1254 untouched benchmarks
⏩ 1254 skipped benchmarks¹

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_{Comparing adamg/df-io-plugin2 (c53838f) with develop (edeef00)}

Footnotes

1. 1254 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.91%. Comparing base (b7a7027) to head (d946f03).
⚠️ Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
vortex-datafusion/src/persistent/source.rs	46.15%	7 Missing ⚠️

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