netns_new()/netns_free() create/delete network namespaces. They support the
option '-m' of test_progs to start/stop traffic monitor for the network
namespace being created for matched tests.
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240815053254.470944-4-thinker.li@gmail.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>