Add option to show environment indicator all the time instead of giving permission to each role

I guess I am only one needing this :)
I've updated fork

I am willing to improve it based on maintainers feedback.

Thank you for your inquiry, I've updated the issue summary. I welcome a merge request

I've set a release target for 🌱 Draft: Release Plan for Environment Indicator Minor Release 5.0.0-beta1 Active

Updated merge request to match newest additions
Updated README

Hi @holo96,

In light of ✨ Performance Improvements Active , I think we should take a slightly different approach.

Rather than putting hasAccess() on the service, I’d propose a new helper in environment_indicator.module that calls less heavy functions like this:

/**
 * Check if user has access to environment indicator.
 *
 * This function checks both the traditional permission and the new
 * unrestricted access setting.
 *
 * @return \Drupal\Core\Session\AccountProxyInterface|false
 *   The current user account if access is granted, FALSE otherwise.
 */
function _environment_indicator_has_access() {
  $account = \Drupal::currentUser();

  // Check if unrestricted access is enabled in settings.php.
  if (Settings::get('environment_indicator_unrestricted_access', FALSE)) {
    return $account;
  }

  // Fall back to traditional permission check.
  if ($account->hasPermission('access environment indicator')) {
    return $account;
  }

  return FALSE;
}

See https://git.drupalcode.org/project/environment_indicator/-/merge_request...

Additionally, I think we should find a way to let users know that they have this setting set in settings.php.

From my perspective, site admins will likely not remember they have this setting set in settings.php and will begin pulling their hair out.

I think we should add a notice on the `/admin/config/development/environment-indicator` page if the setting is enabled.

Additionally, I think we should add some PHPUnit tests so we can feel confident about the feature functioning as expected in future updates.