MFH: r491513

mail/pop3proxy: Fix build with OpenSSL 1.1.1

• Add license
• Fix config file location
• Reorder some things to pet portlint
• Mark it deprecated too as it appears to have no upstream anymore and only works properly with unencrypted traffic

PR: 232134
Submitted by: freebsd_ports@k-worx.org

Approved by: ports-secteam (miwi)