Add Reverse Dynamic Forwarding

[blacknon]

like OpenSSH v7.6, ssh -R 1080.

[ghost-ng]

I am looking into this too (more synonymous with the -D command) - trying to figure out how to do this with the Socks proxy function

[blacknon]

openssh source code

https://github.com/openssh/openssh-portable/blob/667fec5d4fe4406745750a32f69b5d2e1a75e94b/channels.c#L1592-L1648