feat(medusa, medusa-js, medusa-react): Implement Sales Channel list (#1815)

**What**
Support sales channel list in medusa, medusa-js and medusa-react

**How**

By implementing a new endpoint and the associated service method as well as the repository methods.

Medusa-js new list method in the resource

Medusa-react new hook in the queries

**Tests**

Endpoint test
Service test
Integration test
Hook tests

Fixes CORE-280

packages/medusa-react/mocks/data/fixtures.json

@@ -1270,6 +1270,15 @@
       "updated_at": "2022-07-05T15:16:01.959Z",
       "created_at": "2022-07-05T15:16:01.959Z",
       "deleted_at": null
-    }
+    },
+    "sales_channels": [{
+      "id": "sc_01F0YES4R67TXXC1QBQ8P54A8Y",
+      "name": "sales channel 1 name",
+      "description": "sales channel 1 description",
+      "is_disabled": false,
+      "updated_at": "2022-07-05T15:16:01.959Z",
+      "created_at": "2022-07-05T15:16:01.959Z",
+      "deleted_at": null
+    }]
   }
 }