Introduce new InventorySales module

[maghamed]

For all the operations related to Sales and Inventory to follow good modularity principles new module - InventorySales should be created

Read more details in the scope of this story - https://github.com/magento-engcom/msi/wiki/Stocks-to-Sales-Channel-Mapping

[naydav]

#173
#150