Add simple route-based code splitting

package.json

@@ -13,6 +13,7 @@
     "node-sass": "^4.12.0",
     "react": "^16.8.6",
     "react-dom": "^16.8.6",
+    "react-loadable": "^5.5.0",
     "react-router-dom": "^5.0.1",
     "react-scripts": "3.0.1",
     "typescript": "3.5.3"
@@ -45,6 +46,7 @@
   "devDependencies": {
     "@types/cheerio": "^0.22.12",
     "@types/node-fetch": "^2.5.0",
+    "@types/react-loadable": "^5.5.1",
     "@types/request": "^2.48.2",
     "@welldone-software/why-did-you-render": "^3.2.1",
     "cheerio": "^1.0.0-rc.3",