refactor: improve error handling in storage module

[xushiyan]

• Change return values to Result<> for APIs in storage module for better error handling flows.
• Concat RecordBatches into one for get_parquet_file_data()

[codecov]

Codecov Report

Attention: Patch coverage is 88.75000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 88.84%. Comparing base (199a25d) to head (a3a9b87).

Files	Patch %	Lines
crates/core/src/storage/mod.rs	87.14%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #34      +/-   ##
==========================================
- Coverage   90.63%   88.84%   -1.79%     
==========================================
  Files          10       10              
  Lines         491      511      +20     
==========================================
+ Hits          445      454       +9     
- Misses         46       57      +11     

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