feat: remove .env && add eslint env var

Author: Powenga

package.json

@@ -29,7 +29,7 @@
     "superagent-promise": "^1.1.0"
   },
   "scripts": {
-    "start": "cross-env PORT=4100 REACT_APP_API_ROOT=http://localhost:3000/api react-scripts start",
+    "start": "cross-env PORT=4100 REACT_APP_API_ROOT=http://localhost:3000/api ESLINT_NO_DEV_ERRORS=true react-scripts start",
     "build": "react-scripts build",
     "test": "cross-env PORT=4100 react-scripts test --env=jsdom",
     "eject": "react-scripts eject",