feat: refactor rest signer in fileio #2862
Description
Feature Request / Improvement
Context: #2846 (comment)
Currently S3 signer is tightly coupled with FileIO. This is awkward since the S3 Signer requires interaction with remote service (i.e. REST Catalog) and reuse its auth manager.
We can refactor here and create the signer in REST Catalog and pass to FileIO by overriding its _load_file_io function.
Also see _init_sigv4 for inspiration