Add support for interacting with detached containers

[tfoote]

We identified in #320 that there's a possibility for reattaching and interacting with detached containers. Right now rocker doesn't support that, but it could be very helpful for some use cases. It should be possible to have interactive containers with the persistent inputs which then can be attached and detached as desired.

[krishnavasnani07]

Hi! I’m interested in working on this issue.

I’ve gone through the codebase and believe I understand the problem.
If no one else is currently working on it, I’d like to take this up.
I’ll post updates here as I make progress.

Thanks!
Krishna