This pull request introduces a new database migration to ensure that the SSL flag in the database correctly reflects the presence of valid Let's Encrypt certificates for existing sites. The migration checks for orphaned redirect configuration files, verifies SSL certificate issuers, and updates the database as needed, logging all actions for traceability.

Key changes in the migration:

SSL flag correction and certificate validation:

• Added a migration (FixSslFlagForExistingLeCerts) that iterates over all sites, checks for the presence and validity of Let's Encrypt certificates, and updates the site_ssl flag in the database to 'le' if a valid Let's Encrypt certificate is detected.
• Removes orphaned redirect configuration files if corresponding certificates are missing, and reloads the nginx proxy to apply changes.
• Logs detailed actions and decisions for each site to a dedicated log file for auditing and troubleshooting purposes.