`transcode --dry-run` is confusing and/or redundant

[RogueOneEcho]

The implementation of --dry-run differed from my expectation

Typically a --dry-run would go through the steps without actually doing anything.

However, the implementation here is spectrograms and transcodes are still generated and the only step that is skipped is uploading.

This behaviour is already handled by --automatic-upload false - which in fact does a better job because it prints the data that would be uploaded to the terminal.