Optionally skip "output" & "diff" upload to S3

If [S3 (AWS, DigitalOcean, etc.) is configured](https://github.com/codeceptjs/codeceptjs-resemblehelper/blob/da3858f51ecff56919260bba8b1a926f29737a57/README.md#aws-support), this helper downloads and uploads `output` (actual), `base` and `diff` images to the S3 storage.

However for a regular CI workflow it does not make sense to have `diff` images uploaded:

1. They only make sense for the particular CI run with the particular source code state
2. The result in the S3 storage is undefined in case of other CI runs executed in parallel or other CI pipelines

Thus it would be useful to have an option to skip the upload of `diff` images to S3. Instead they should only be stored locally in this case.

Notice that the same goes for `output` (actual) for the same reasons listed above. Updating the `base` images should always be done locally