feat(medusa): Performance improvements of Carts domain (#2648)

**What**

I have created a new method on the cart service which is `addLineItems`, allowing a user to add one or multiple items in an optimized way. Also updated the `generate` method from the line item service which now also accept a object data or a collection of data which. Various places have been optimized and cache support has been added to the price selection strategy.

The overall optimization allows to reach another 9000% improvement in the response time as a median (Creating a cart with 6 items):

|   | Min (ms)  | Median (ms)  | Max (ms)  | Median Improvement (%)
|---|:-:|---|---|---|
| Before optimisation  | 1200  | 9999 | 12698  |  N/A
| After optimisation | 63  | 252  | 500  | 39x
| After re optimisation | 56 | 82  | 399  | 121x
| After including addressed feedback | 65 | 202  | 495  | 49x

FIXES CORE-722

integration-tests/api/package.json

@@ -8,16 +8,16 @@
     "build": "babel src -d dist --extensions \".ts,.js\""
   },
   "dependencies": {
-    "@medusajs/medusa": "1.6.5-dev-1669708431707",
+    "@medusajs/medusa": "1.6.5-dev-1670340951307",
     "faker": "^5.5.3",
-    "medusa-interfaces": "1.3.3-dev-1669708431707",
+    "medusa-interfaces": "1.3.3-dev-1670340951307",
     "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-1669708431707",
+    "babel-preset-medusa-package": "1.1.19-dev-1670340951307",
     "jest": "^26.6.3"
   }
 }