Double check Order#adjustments are serialized properly according to order object documentation

[AlessioRocco]

Looking at the wombat order object documenation it appears that adjustments are different from those generated by the order serializer.
I've also noticed that in this issue @huoxito changed this behavior.
Does this need to be fixed or should it be kept this way?

If you want I can open a pull request.

[huoxito]

hey @AlessioRocco how different you think the current order serializer adjustments is different from what the doc says? We should probably add things like discounts too in the adjustments array but I can't see how the format is different now. Either way feel free to submit the PR please, always better to discuss over some code.

[peterberkenbosch]

@AlessioRocco Working on improving this.