nixos/grafana: fix w/o datasources or dashboard provisioning

  settingsFormatIni = pkgs.formats.ini {};

  configFile = settingsFormatIni.generate "config.ini" cfg.settings;

  datasourceFile = if (cfg.provision.datasources.path == null) then provisioningSettingsFormat.generate "datasource.yaml" cfg.provision.datasources.settings else cfg.provision.datasources.path;

  mkProvisionCfg = name: attr: provisionCfg:

    if provisionCfg.path != null

      then provisionCfg.path

    else

      provisioningSettingsFormat.generate "${name}.yaml"

        (if provisionCfg.settings != null

          then provisionCfg.settings

          else {

            apiVersion = 1;

            ${attr} = [];

          });

  dashboardFile = if (cfg.provision.dashboards.path == null) then provisioningSettingsFormat.generate "dashboard.yaml" cfg.provision.dashboards.settings else cfg.provision.dashboards.path;

  datasourceFile = mkProvisionCfg "datasource" "datasources" cfg.provision.datasources;

  dashboardFile = mkProvisionCfg "dashboard" "providers" cfg.provision.dashboards;

  notifierConfiguration = {

    apiVersion = 1;