nixos: services: servarr: extract bazarr

It's not an actual *arr package, but closely related to them. Extract
its configuration to a sub-module.

modules/nixos/services/servarr/bazarr.nix

@@ -0,0 +1,29 @@
+{ config, lib, ... }:
+let
+  cfg = config.my.services.servarr.bazarr;
+in
+{
+  options.my.services.servarr.bazarr = with lib; {
+    enable = lib.mkEnableOption "Bazarr" // {
+      default = config.my.services.servarr.enableAll;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.bazarr = {
+      enable = true;
+      group = "media";
+    };
+
+    # Set-up media group
+    users.groups.media = { };
+
+    my.services.nginx.virtualHosts = {
+      bazarr = {
+        port = 6767;
+      };
+    };
+
+    # Bazarr does not log authentication failures...
+  };
+}