tools/thermal: Add a temperature capture tool

The 'thermometer' tool allows to capture the temperature of a set of
thermal zones defined in a configuration file at a specified rate.

It is designed to have the lowest possible overhead. It will write the
captured temperature per thermal zone per file so making easier to
write a gnuplot script.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20220420160933.347088-4-daniel.lezcano@linaro.org