samples: mesh: nrf52: Time filtering, Coding style & others

Added time stamp based message filtering as per Bluetooth Mesh
Developer study guide for each Server. Now even if message
source address & TID is same even after 6 seconds then
that will get proceed otherwise will get ignored.

Coding style improvements.

If particular Server model receive Prohibited values as per
Mesh Model Specification then that message will not get entertained.

Now proper status code will get send if user upgrade
light_lightness_range_state & light_ctl_temperature_range_state.

Signed-off-by: Vikrant More <vikrant8051@gmail.com>