Fix Riot caching troubles

Some resources shouldn't be cached right now,
as per https://github.com/vector-im/riot-web/pull/8702

(note all of the suggestions from that pull request were applied,
because some of them do not seem relevant - no such files)

Fixes #98 (Github Issue)

roles/matrix-riot-web/templates/nginx.conf.j2

@@ -47,11 +47,16 @@ http {
 		listen 8080;
 		server_name localhost;
 
+		root /usr/share/nginx/html;
+
 		location / {
-			root /usr/share/nginx/html;
 			index index.html index.htm;
 		}
 
+		location ~* ^/(config(.+)?\.json$|(.+)\.html$|i18n) {
+			expires -1;
+		}
+
 		error_page 500 502 503 504 /50x.html;
 		location = /50x.html {
 			root /usr/share/nginx/html;