netavark: add new package

netavark: add new package

podman is moving from cni to netavark. Netavark supports currently
only iptables, so I was in touch some time ago with mainstream
maintainer and provided a "none" firewall driver - to make it possible
to use netavark without firewalling features. Driver cannot be selected
at this time without environment variable that selects it, so I made
a config file for openwrt and a wrapper script that takes advantage of
it.

Available options are iptables, nftables and none - but selecting
nftables just tells user that nftables isn't yet supported.

firewall "none" driver is not yet included in release, so that's why
we use git version instead. I chose latest commit instead of commit
with none driver.

Description:
Netavark is a rust based network stack for containers.
It is being designed to work with Podman but is also applicable for other OCI container management applications.

Signed-off-by: Oskari Rauta <oskari.rauta@gmail.com>