net: shell: Remove net-app command
net: shell: Remove net-app command

The "net app" command is not needed any more as the API is removed.

Signed-off-by: Jukka Rissanen <f9f077d1da4c7aa947f9864fa5a28c3588f6a45d@linux.intel.com>

Vudentz/zephyr,explora26/zephyr,galak/zephyr,Vudentz/zephyr,ldts/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,explora26/zephyr,finikorg/zephyr,ldts/zephyr,finikorg/zephyr,ldts/zephyr,explora26/zephyr,explora26/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,nashif/zephyr,ldts/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,galak/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr