password_policy.install

<?php

use Drupal\field\Entity\FieldStorageConfig;

/**
 * Implements hook_install().
 */
function password_policy_install() {
  //set user password reset timestamp to now
  $users = \Drupal::entityManager()->getStorage('user')->loadMultiple();
  $date = date('Y-m-d\TH:i:s');
  foreach ($users as $user) {
    $user->set('field_last_password_reset', $date);
    $user->set('field_password_expiration', '0');
    $user->save();
  }

  //rebuild user entity form display for new fields.
  $config = \Drupal::service('config.factory')->getEditable('core.entity_form_display.user.user.default');

  // Not sure why this isn't set, but it throws an error in simpletest.
  $config->set('targetEntityType', 'user');
  $config->set('bundle', 'user');

  $dep_module = $config->get('dependencies.module');
  $dep_module[] = 'field.field.user.user.field_last_password_reset';
  $dep_module[] = 'field.field.user.user.field_password_expiration';
  $config->set('dependencies.module', $dep_module);

  $dep_config = $config->get('dependencies.config');
  $dep_config[] = 'field.field.user.user.field_last_password_reset';
  $dep_config[] = 'field.field.user.user.field_password_expiration';
  $config->set('dependencies.config', $dep_config);


  $last_password_reset = [
    'type' => 'datetime_default',
    'weight' => '6',
    'settings' => [],
    'third_party_settings' => [],
  ];
  $config->set('content.field_last_password_reset', $last_password_reset);

  $field_password_expiration = [
    'type' => 'boolean_checkbox',
    'weight' => '5',
    'settings' => ['display_label' => 'true'],
    'third_party_settings' => [],
  ];
  $config->set('content.field_password_expiration', $field_password_expiration);

  $config->save();

}