Add support for providing random shift and random provider to batch

[pattonw]

Pre-Merge Checklist:

• [x] if this PR adds a feature: request merge into the latest development branch (vX.Y-dev)
• [x] PR branch name is short and describes the feature/bug addressed in this PR
• [x] commit messages are consistent
• [ ] changes reviewed by another contributor
• [x] tests cover changes
• [x] all tests pass

You can now provide the RandomLocation node an array key which it will populate with the random shift chosen for each batch. You can now provide the RandomProvider node an array key which it will populate with the index of the random provider chosen for each batch.

TODO: same thing for other random nodes such as elastic augment, shift augment etc.