refactor: remove hardcoded credentials from config

- Strip configuration.local.php to logger-only defaults
- Remove db, solr, session, checkfile_url, worker IDs (unused legacy)
- Clean credential comments from logger config files
- Add .env.example template
- Add .env to .gitignore

.gitignore

@@ -2,3 +2,4 @@ vendor/
 *.swp
 output
 composer.lock
+.env