feat(medusa): Add ProductVariantInventoryService (#2883)

* add mw feature flag

* add services

* add types

* add module interfaces

* add interface export

* add models for mw

* to be ammended

* remove featureflag

* use correct count

* update cart completion strategy

* swap service conversion

* update return service

* update order service

* update claim service

* add exception to claim item

* update cart service

* add indicies

* add changeset

* nullable changes in store

* store model update

* fix unit tests

* remove old inventory service

* format integration test

* update snapshots

* remove old inventory service tests

* update snapshots

* remove old code

* option updates

* naming

* add jsdoc to pv inventory service

* rename class variables

* pr feedback

* rename option to context

* if(variant_id) instead of if(typeof varia...)

* update tests

* add jsdoc

* go for custom

* update code for readability

integration-tests/plugins/__tests__/medusa-plugin-sendgrid/__snapshots__/index.js.snap

@@ -566,6 +566,7 @@ Object {
             "return_id": Any<String>,
           },
         ],
+        "location_id": null,
         "metadata": null,
         "no_notification": null,
         "order_id": Any<String>,
@@ -709,6 +710,7 @@ Object {
         "return_id": Any<String>,
       },
     ],
+    "location_id": null,
     "metadata": null,
     "no_notification": null,
     "order_id": Any<String>,
@@ -1737,6 +1739,7 @@ Object {
             "return_id": Any<String>,
           },
         ],
+        "location_id": null,
         "metadata": null,
         "no_notification": null,
         "order_id": Any<String>,
@@ -1880,6 +1883,7 @@ Object {
         "return_id": Any<String>,
       },
     ],
+    "location_id": null,
     "metadata": null,
     "no_notification": null,
     "order_id": Any<String>,
@@ -2400,6 +2404,7 @@ Object {
           "return_id": Any<String>,
         },
       ],
+      "location_id": null,
       "metadata": null,
       "no_notification": null,
       "order_id": null,