feature: handle asciicast v2 `input` and `marker` event codes

[azerella]

sshpiper does not handle recording input or markers event types as per the asciicast > v2 event spec. All commands are logged as o / output instead of recording user input?

Is this a bug or a feature or the SSH session?

See the asciicast v2 event code spec:

https://docs.asciinema.org/manual/asciicast/v2/#supported-event-codes

[tg123]

sshpiper record the result from upstream only, so everything was treated as output