Persistent rooms via Firebase (#2188)

* Periodically back up collaborative rooms in firebase

* Responses to code review

* comments from code review, new firebase credentials

package.json

@@ -29,6 +29,7 @@
     "@types/react-dom": "16.9.8",
     "@types/socket.io-client": "1.4.33",
     "browser-nativefs": "0.10.3",
+    "firebase": "7.21.1",
     "i18next-browser-languagedetector": "6.0.1",
     "lodash.throttle": "4.1.1",
     "nanoid": "2.1.11",
@@ -49,6 +50,7 @@
     "eslint": "6.8.0",
     "eslint-config-prettier": "6.12.0",
     "eslint-plugin-prettier": "3.1.4",
+    "firebase-tools": "8.11.2",
     "husky": "4.3.0",
     "jest-canvas-mock": "2.2.0",
     "lint-staged": "10.4.0",