**what**
Support `updateLineItem` which does the following:
- If no item change exist then create a new one and attaches the clone item with the adjustments and tax lines
- if an item change exists then delete/create adjustments and tax lines and update the cloned item quantity
**Tests**
- Unit tests core + client
- integration tests
- When no item change already exists
- When an item change already exists
FIXES CORE-497
Adrien de Peretti
474e97252c