feat: add notification UI

showPopup was also refactored to be better

frontend/package.json

@@ -28,6 +28,7 @@
     "@types/react-router": "^5.1.4",
     "@types/react-router-dom": "^5.1.3",
     "@types/react-select": "^3.0.13",
+    "@types/react-timeago": "^4.1.1",
     "@types/styled-components": "^5.0.0",
     "apollo-cache-inmemory": "^1.6.5",
     "apollo-client": "^2.6.8",
@@ -60,6 +61,8 @@
     "react-scripts": "3.4.0",
     "react-select": "^3.1.0",
     "rich-markdown-editor": "^10.6.5",
+    "react-timeago": "^4.4.0",
+    "react-toastify": "^6.0.8",
     "styled-components": "^5.0.1",
     "typescript": "~3.7.2"
   },