Add a resolver

This commit adds a resolver to the toplevel Distillery domain, to allow
resolving domains globally.

distillery/resources/compose/resolver/docker-compose.yml

@@ -0,0 +1,29 @@
+version: "3.7"
+
+services:
+  wdresolve:
+    image: ghcr.io/fau-cdi/wdresolve:latest
+    restart: always
+    volumes:
+      - "${PREFIX_FILE}:/prefixes.cfg:ro"
+    environment:
+      # port and hostname for this image to use
+      VIRTUAL_HOST: ${VIRTUAL_HOST}
+      VIRTUAL_PORT: 8080
+      VIRTUAL_PATH: /go/
+      
+      # optional letsencrypt email
+      LETSENCRYPT_HOST: ${LETSENCRYPT_HOST}
+      LETSENCRYPT_EMAIL: ${LETSENCRYPT_EMAIL}
+
+      # default and legacy domain
+      DEFAULT_DOMAIN: ${DEFAULT_DOMAIN}
+      LEGACY_DOMAIN: ${LEGACY_DOMAIN}
+
+      # the prefix file
+      PREFIX_FILE: /prefixes.cfg
+
+networks:
+  default:
+    external:
+      name: distillery