[blob-service] Use new error types in S3 functions

Summary:
Part of ENG-2398 - replaces anyhow with S3-specific error types in database functions.

Depends on D8100

Test Plan: Played with these by providing invalid inputs to S3 SDK functions (e.g. non-existing object or incorrect S3 path) - using format!("Error: {:?}", s3_error) displayed correct error types.

Reviewers: jon, varun, michal

Reviewed By: varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8101