Docker secrets do not belong in stand alone containers.

Patch update.php to allow successful upgrades past 4.0

1. Added support for crontag scheduled campaigns, autoresponders and …

…CSV imports.

1. Added support for HTTPS through environment variable `SENDY_PROTOCOL`.
1. Updated docker-compose:
    1. To use `sendy.env` environment file for simplified variable management.
    1. Added HAProxy load balancer for SSL termination.  HAProxy initialization script will generate developer rootCA and SSL certificates for domain `SENDY_FQDN` if /etc/cert/server.pem does not exist.
1. Updated README to reflect new environment variable.

only whitespace changes...