Keep RabbitMQ data on recreate and proxy to unique container names

RabbitMQ stores its data under rabbit@<hostname>, and the hostname
changed with every recreated container, so an image update or an .env
change came up with an empty broker. Pin it to `rabbitmq` and document
how to carry the definitions over on an existing deployment.

Every project shares infra-net, where a generic service name like `api`
resolves to every container that has it, round-robin, across projects.
The edge now proxies to container names (musify-api, infra-zitadel, ...).

edge/conf.d/musify.conf

@@ -27,7 +27,7 @@ server {
     include /etc/nginx/snippets/tls.conf;
 
     location / {
-        set $upstream http://web-player:3000;
+        set $upstream http://musify-web-player:3000;
         proxy_pass $upstream;
         include /etc/nginx/snippets/proxy.conf;
     }
@@ -44,7 +44,7 @@ server {
     include /etc/nginx/snippets/tls.conf;
 
     location / {
-        set $upstream http://api:5111;
+        set $upstream http://musify-api:5111;
         proxy_pass $upstream;
         include /etc/nginx/snippets/proxy.conf;
     }
@@ -62,7 +62,7 @@ server {
     include /etc/nginx/snippets/tls.conf;
 
     location / {
-        set $upstream http://gateway:8081;
+        set $upstream http://musify-gateway:8081;
         proxy_pass $upstream;
         include /etc/nginx/snippets/proxy.conf;
         proxy_buffering off;
@@ -88,7 +88,7 @@ server {
     }
 
     location / {
-        set $upstream http://zitadel:8080;
+        set $upstream http://infra-zitadel:8080;
         proxy_pass $upstream;
         include /etc/nginx/snippets/proxy.conf;
     }
@@ -107,7 +107,7 @@ server {
     include /etc/nginx/snippets/tls.conf;
 
     location / {
-        set $upstream http://seaweedfs:8333;
+        set $upstream http://infra-seaweedfs:8333;
         proxy_pass $upstream;
         include /etc/nginx/snippets/proxy.conf;
         proxy_request_buffering off;