[misc] rename npm-shrinkwrap.json to package-lock.json and run npm i

Also delete unused redis dependency.

services/spelling/package-lock.json

@@ -3624,11 +3624,6 @@
         }
       }
     },
-    "redis": {
-      "version": "0.8.6",
-      "resolved": "https://registry.npmjs.org/redis/-/redis-0.8.6.tgz",
-      "integrity": "sha1-p66PDW+tJL3q/+KBWNbNHxydMLg="
-    },
     "regexpp": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/regexpp/-/regexpp-2.0.1.tgz",

services/spelling/package.json

@@ -34,7 +34,6 @@
     "metrics-sharelatex": "^2.2.0",
     "mongojs": "2.4.0",
     "node-statsd": "0.0.3",
-    "redis": "~0.8.4",
     "request": "^2.88.0",
     "settings-sharelatex": "^1.1.0",
     "underscore": "1.9.1"