Feature #1196 Multi Source Inventory support

[rbayet]

Created an additional module with a somewhat evocative name, but I'm not so sure about it anymore, since \Magento\CatalogInventory\Api\StockRegistryInterface and \Magento\CatalogInventory\Api\StockConfigurationInterface are cleared marked as deprecated (see full list in https://devdocs.magento.com/guides/v2.3/inventory/catalog-inventory-replacements.html).

Having the changes directly in elasticsuite-catalog would remove the need for the extra interface I had to introduce.

[romainruaud]

Impressive ! seems it was pretty easy after all :)

I'm not sure either about the additional module :

• implementation looks quite transparent to me, and could probably be done directly on the ElasticsuiteCatalog module directly.

• in any cases, hoping for BC with such huge changes, by having an additional module which is meant to be disabled on 2.2.x is kinda risky (could double the maintenance time), in addition of being quite ugly and not easily understandable.

• the Interface for Stock data fetching suits me well, we can keep it, it will allow people to write their own and switch the implementation nicely, so we can keep it.

Let's talk about it together today, but we'll probably go for a direct implementation on ElasticsuiteCatalog, and having a 2.7.0 major version which requires Magento >= 2.3.0.