test: hsr: Extend the hsr_redbox.sh to have more SAN devices connected

After this change the single SAN device (ns3eth1) is now replaced with
two SAN devices - respectively ns4eth1 and ns5eth1.

It is possible to extend this script to have more SAN devices connected
by adding them to ns3br1 bridge.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Link: https://lore.kernel.org/r/20240510143710.3916631-1-lukma@denx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

test: hsr: Call cleanup_all_ns when hsr_redbox.sh script exits

Without this change the created netns instances are not cleared after
this script execution. To fix this problem the cleanup_all_ns function
from ../lib.sh is called.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

test: hsr: Add test for HSR RedBOX (HSR-SAN) mode of operation

This patch adds hsr_redbox.sh script to test if HSR-SAN mode of operation
works correctly.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>