[mcp] Reorganizing container files

system/hosts/mcp/containers/shared-postgres.nix

@@ -0,0 +1,16 @@
+# Shared Postgres Database
+{ ... }:
+{
+  virtualisation.oci-containers.db = {
+    image = "docker.io/postgres:16-alpine";
+    autoStart = true;
+    volumes = [
+      # TODO: move to faster storage?
+      "/tank/db:/var/lib/postgresql/data"
+    ];
+    environment = {};
+    extraOptions = [
+      "-l=traefik.enable=false"
+    ];
+  };
+}