Add support for enable_ipv6

[claraphyll]

Fixes #751

This pull request adds support for the enable_ipv6 network option when creating the network. This is supported by docker compose and is contained in the compose-spec [1]. The change simply exposes the --ipv6 option of podman network create

PS: One could argue that this should be on by default and only disabled when enable_ipv6: false is set, but doing something like that should - if we even choose to do it at all - be delayed at the very least until https://github.com/containers/podman/issues/15850 is fixed.

[1] https://github.com/compose-spec/compose-spec/blob/master/06-networks.md#enable_ipv6

[sgryphon]

This is important. Please merge.

[pini-gh]

Anything preventing this to be merged?

[p12tic]

@maxi0604 Just a note that podman-compose has switched to main as the primary branch. You probably rebased against devel.

[p12tic]

Also probably a nitpick, but it would be great if extraction of get_network_create_args would be the first commit. This way the amount of changes to code not under unit tests would be minimized.

[p12tic]

Rebased and reordered commits.