containers.conf.5.md needs to be updated for Pasta

[jklaiho]

In the "Engine table" section in containers.conf.5.md, network_cmd_path and network_cmd_options are specific to slirp4netns. With Pasta now the recommended (AFAIK) option in later Podman versions, some mention of it should probably be added to that file.

I have no idea if those two options (or some new, so far undocumented options) are applicable to Pasta, but even if not, it would be helpful to add a clarification about it near the slirp4netns bits.

[Luap99]

pasta does not use either of these fields

The pasta path can be set via helpers_binaries_dir it will search the list of directories there, pasta options cannot be set in containers.conf right now. We could add a new field for this if needed, we should definitely not use the same one because one might use both pasta and slirp and the options would conflict.