If the duration to publish is roughly the same as the period, we might
end up with elapsed == period, which returns 0 and cancel the periodic
publication. Instead 1 should be returned, just like when the elapsed
time is greater than the period.
Creates macros for determining model message lengths based on opcode,
payload length and MIC size. Also adds macro wrapping
NET_BUF_SIMPLE_DEFINE to serve the most common use case.
