podman stats polled by default in a 1 sec period.
This can put quite some load on a machine if you run many containers.
The default value is now 5 seconds.
You can change this interval with a new, optional, --interval, -i cli flag.
The api request got also a interval query parameter for the same purpose.
Additionally a unused const was removed.
Api and cli will fail the request if a 0 or negative value is passed in.
Signed-off-by: Thomas Weber <towe75@googlemail.com>