shell: report thread runtime stats
shell: report thread runtime stats

Updates the kernel service to display the extended thread
runtime stats when the following shell command is issued.

 kernel threads

Signed-off-by: Peter Mitsis <22bf95476f8cdbda3c8a9a9bf1bdda876f69ea7a@intel.com>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr