refactor(deploy): rename the frontend service to web-player

Matches the folder rename: compose service frontend -> web-player,
container musify-frontend -> musify-web-player, and the nginx upstream
now points at http://web-player:3000.

Deploying this needs --remove-orphans, or the old musify-frontend
container is left behind.

deploy/nginx/conf.d/musify.conf

@@ -110,7 +110,7 @@ server {
     ssl_certificate_key /etc/nginx/certs/origin.key;
 
     location / {
-        set $upstream http://frontend:3000;
+        set $upstream http://web-player:3000;
         proxy_pass $upstream;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;