Add storage options to make it easy to setup storage for rootless.

[rhatdan]

containers/podman#4551

[vrothberg]

I wonder if we should put that into storage.conf instead? Are there rules to discriminate which kinds of options go into storage.conf and which into containers.conf?

(copied from containers/podman#4551)

Yes this is the containers.conf stuff that is being worked on.
One thing we would need there is a mechanism to specify the homedir for rootless users
graphroot=$HOME/.local/share/containers/storage
And change it to
graphroot=/var/tmp/$USER/containers/storage

And have to tools smart enough to substiture $HOME or $USER when setting up the storage.

This sounds like something, where I initially think of a storage.Graphroot(user string) (string, error) and let c/storage do the magic.

[rhatdan]

I am fine with that. and it makes some sense. I started working on a patch to handle this yesterday. I can see about moving it into container/storage. I will push a WIP PR so we can record it.

[rhatdan]

Current PR. containers/storage#529