fix(medusa): Optimize Cart totals calculation (#2372)

**What**

The existing totals calculations are extremely heavy and perform an enormous amount of duplicate work. The changes here remove large parts of the overhead and improves response times for cart endpoints up to 30x.

integration-tests/plugins/.yarnrc.yml

@@ -0,0 +1,4 @@
+npmRegistryServer: "http://localhost:4873"
+
+unsafeHttpWhitelist:
+  - localhost

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

@@ -328,7 +328,6 @@ Object {
       "title": "Intelligent Plastic Chips",
       "totals": Object {
         "discount_total": 0,
-        "gift_card_total": 0,
         "original_tax_total": 200,
         "original_total": 1200,
         "quantity": 1,
@@ -1022,7 +1021,6 @@ Object {
       "title": "Intelligent Plastic Chips",
       "totals": Object {
         "discount_total": 0,
-        "gift_card_total": 0,
         "original_tax_total": 400,
         "original_total": 2400,
         "quantity": 2,
@@ -1477,7 +1475,6 @@ Object {
       "title": "Intelligent Plastic Chips",
       "totals": Object {
         "discount_total": 0,
-        "gift_card_total": 0,
         "original_tax_total": 200,
         "original_total": 1200,
         "quantity": 1,

integration-tests/plugins/package.json

@@ -8,18 +8,18 @@
     "build": "babel src -d dist --extensions \".ts,.js\""
   },
   "dependencies": {
-    "@medusajs/medusa": "1.2.1-dev-1649009241281",
+    "@medusajs/medusa": "1.4.1-dev-1665082901122",
     "faker": "^5.5.3",
-    "medusa-fulfillment-webshipper": "1.2.1-dev-1649009241281",
-    "medusa-interfaces": "1.2.1-dev-1649009241281",
-    "medusa-plugin-sendgrid": "1.2.1-dev-1649009241281",
+    "medusa-fulfillment-webshipper": "1.3.3-dev-1665082901122",
+    "medusa-interfaces": "1.3.3-dev-1665082901122",
+    "medusa-plugin-sendgrid": "1.3.3-dev-1665082901122",
     "typeorm": "^0.2.31"
   },
   "devDependencies": {
     "@babel/cli": "^7.12.10",
     "@babel/core": "^7.12.10",
     "@babel/node": "^7.12.10",
-    "babel-preset-medusa-package": "1.1.19-dev-1649009241281",
+    "babel-preset-medusa-package": "1.1.19-dev-1665082901122",
     "jest": "^26.6.3"
   }
 }