Fix #48: Proper 404 and 403 pages when trying to open non-existant chatroom (WIP).

package.json

@@ -35,6 +35,7 @@
   "dependencies": {
     "async": "^3.2.2",
     "decache": "^4.6.0",
+    "escape-html": "^1.0.3",
     "got": "^11.8.2",
     "http-proxy": "^1.18.1",
     "log-rotate": "^0.2.8",
@@ -46,6 +47,7 @@
     "@peertube/peertube-types": "^5.2.0",
     "@tsconfig/node12": "^1.0.9",
     "@types/async": "^3.2.9",
+    "@types/escape-html": "^1.0.4",
     "@types/express": "^4.17.13",
     "@types/got": "^9.6.12",
     "@types/http-proxy": "^1.17.9",