allow explicit TLS access for external ftp storage

[michaelberg79]

Is your feature request related to a problem? Please describe.
I need to add an external storage to a ftp client. This ftp-server is secured by explcit tsl. The connection needs to be secured after the handshake.

Describe the solution you'd like
I would like an option to add ftp-server with explcit tsl connections. Currently there are only implicit tsl connections allowed.

[joshtrichards]

The underlying code uses PHP's ftp_ssl_connect(). This is already exclusively Explicit mode FTP.

https://www.php.net/manual/en/function.ftp-ssl-connect.php