Fixup no_trainer save logic
# Fix save logic in all `no_trainer` examples

## What does this add?

This PR fixes a bug pointed out in https://github.com/huggingface/accelerate/issues/322, where the save and load logic was wrong in how it skipped over the steps in the training loop.

This PR fixes it and changes the internals slightly to let saveing of a checkpoint be named right (before it always started at `epoch_0`, even if we resumed from epoch 1
_The documentation is not available anymore as the PR was closed or merged._