Deploy a reverse proxy doing PROXY Protocol

This is needed to be able to nicely host multiple services under a
single IPv4.
The reverse proxy also includes a configuration to pass requests for
acme challenge properly.
And lastly the reverse proxy is already configured for a stirling pdf,
which gets added once the DNS record for it is in place.

docker_compose_applications/reverse-proxy/conf.d/acme_challenge.conf

@@ -0,0 +1,23 @@
+map $host $upstream_acme_challenge_host {
+    pdf.consider-it.de 127.0.0.1:8000;
+    default "";
+}
+
+server {
+    listen 80 default_server;
+
+    location /.well-known/acme-challenge/ {
+        proxy_pass http://$upstream_acme_challenge_host;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        # This is http in any case.
+        proxy_set_header X-Forwarded-Proto http;
+    }
+
+    # Better safe than sorry.
+    # Don't do a permanent redirect to avoid acme challenge pain.
+    location / {
+        return 307 https://$host$request_uri;
+    }
+}