add bootstrap script

package.json

@@ -30,6 +30,7 @@
     ]
   },
   "scripts": {
+    "bootstrap": "yarn install --frozen-lockfile",
     "start": "yarn app:server",
     "prestart": "yarn app:build",
     "app:build": "turbo run build --filter @growi/app",

turbo.json

@@ -7,6 +7,14 @@
   ],
   "pipeline": {
 
+    "bootstrap": {
+      "dependsOn": ["//#bootstrap"],
+      "cache": false
+    },
+    "//#bootstrap": {
+      "cache": false
+    },
+
     "clean": {
       "cache": false
     },