Drupal sets read-only permissions on settings.local.php and services.yml

[andrewfrench]

Describe the bug
#916 included the skip_permissions_hardening directive in Drupal8 and ensured that settings.php (and its parent directory) were writable for Drupal 6/7/8. Two additional files, settings.local.php and services.yml, should be added to the list of files that are ensured to be writable.

To Reproduce
Steps to reproduce the behavior (from @rfay):

1. composer setup quickstart (creates a settings.php that doesn't include settings.local.php, commented out)
2. ddev config (creates settings.local, but the skip_permissions_hardening hasn't been done yet because settings.local.php not included)
3. ddev start
4. settings.local.php is read-only

Expected behavior
Settings files should remain writable during development.