workflow: move eslint-config-* packages to standalone repos for easier maintenance

Their upstream packages update much more frequently than most other
packages in this repo, so they are more likely to be subject to breaking
changes, thus requiring a different version strategy.

Author: haoqunjiang

lerna.json

@@ -1,6 +1,6 @@
 {
   "npmClient": "yarn",
-  "useWorkspaces": false,
+  "useWorkspaces": true,
   "version": "4.0.0-alpha.4",
   "packages": [
     "packages/@vue/babel-preset-app",

package.json

@@ -44,6 +44,10 @@
   },
   "devDependencies": {
     "@babel/core": "^7.4.5",
+    "@vue/eslint-config-airbnb": "^4.0.0",
+    "@vue/eslint-config-prettier": "^4.0.1",
+    "@vue/eslint-config-standard": "^4.0.0",
+    "@vue/eslint-config-typescript": "^4.0.0",
     "@vuepress/plugin-pwa": "^1.0.1",
     "@vuepress/theme-vue": "^1.0.1",
     "babel-core": "7.0.0-bridge.0",