chore: Start cleaning up medusa-core-utils (#7450)

**What**
- remove medusa-core-utils
- dispatch the utils where they belongs
- update usage

**NOTE**
I have been wondering if the graceful class should go into the utils package or medusa package, I ve put it in the medusa package as it seems to be the best place I can see for now and is tight to the server as well. Also, I wanted to avoid the utils package to depends on http and net dependencies, happy to change that if you feel like it

packages/core/medusa-test-utils/src/medusa-test-runner-utils/bootstrap-app.js

@@ -2,7 +2,10 @@ const path = require("path")
 const express = require("express")
 const getPort = require("get-port")
 const { isObject, promiseAll } = require("@medusajs/utils")
-const { GracefulShutdownServer } = require("medusa-core-utils")
+// TODO: fix that once we find the appropriate place to put this util
+const {
+  GracefulShutdownServer,
+} = require("@medusajs/medusa/dist/utils/graceful-shutdown-server")
 
 async function bootstrapApp({ cwd, env = {} } = {}) {
   const app = express()
@@ -16,7 +19,6 @@ async function bootstrapApp({ cwd, env = {} } = {}) {
   const { container, shutdown } = await loaders({
     directory: path.resolve(cwd || process.cwd()),
     expressApp: app,
-    isTest: false,
   })
 
   const PORT = await getPort()