Capture mesh-catalog at feat/r4g (2246ccc4) with the templates its manifests name and its predefined.json, and lay the copy out as a repository's root

The catalogue's manifests moved their content into template files and fall back to predefined keys, so a copy of
module.json alone no longer passes the catalogue's own check; the bus's Dockerfile is gone from the catalogue.

testdata/beside/mesh-catalog/modules/n8n/files/n8n-database.secret

@@ -0,0 +1 @@
+${secret:postgres-database}

testdata/beside/mesh-catalog/modules/n8n/files/server.env

@@ -0,0 +1,12 @@
+N8N_HOST=${bound:route:name}
+N8N_PORT=5678
+N8N_PROTOCOL=https
+WEBHOOK_URL=https://${bound:route:name}/
+NODE_FUNCTION_ALLOW_BUILTIN=*
+NODE_FUNCTION_ALLOW_EXTERNAL=*
+DB_TYPE=postgresdb
+DB_POSTGRESDB_HOST=${bound:postgres-database:at}
+DB_POSTGRESDB_PORT=${bound:postgres-database:port}
+DB_POSTGRESDB_DATABASE=${bound:postgres-database:as}
+DB_POSTGRESDB_USER=${bound:postgres-database:as}
+DB_POSTGRESDB_PASSWORD_FILE=/run/secrets/database