Returning output as JSON

**Context**
I am using s4cmd within github actions to upload the files to S3, also i am using `--sync-check` flag to ensure files that are already uploaded are not uploaded again and i am using both `dsync` for directory level sync and combination of `put` and `del` for file level uploads and deletes.

The result can either be that the file is
- already synced and does not require output
- Uploaded
- Deleted

**What i want**
I want this output to be in a json format so that i can easily parse and display the status (synced, uploaded and deleted) in the UI

Start by reviewing the CLI paths for dsync, put, and del, and run them with --sync-check to observe their current output. Define and verify a consistent JSON result that distinguishes already-synced, uploaded, and deleted files and can be parsed by the GitHub Actions UI.

Written by the indexing model from the issue text.