Add S3 File and Folder Operations in S3FileHandler Class

[Alphagon]

Description: This pull request introduces several new features to the S3FileHandler class, providing comprehensive support for interacting with AWS S3. The new methods allow users to list, upload, and download files and folders to and from an S3 bucket.

Key Features:

List Buckets and Objects:
    list_s3_buckets: Lists all S3 buckets in the account.
    list_s3_objects: Lists all files within a specific S3 bucket or under a given prefix.

File Upload:
    upload_file_to_s3: Uploads a file from the local file system to an S3 bucket, with optional metadata support.

File Download:
    download_s3_file: Downloads a specific file from an S3 bucket to a local directory. Optionally retrieves file metadata.

Folder Download:
    download_s3_folder: Recursively downloads an entire folder from an S3 bucket to a local directory while preserving the directory structure.

These enhancements streamline the process of handling files and folders in S3, offering a more user-friendly API to manage S3 resources efficiently.

Changes:

Added new methods for file and folder operations.
Optional metadata handling for file uploads and downloads.

Testing:

Manually tested against various S3 buckets, verifying upload/download functionality and metadata retrieval.