After the addition of bare metal toolchains the menu system allowed
to create non-valid configurations. I reworked it so we can also
add other operating system support if we wish.
So first you choose your operating system, then your architecture
and endianess, after that your embedded system, emulator or
generic device and then you choose your task you want to run.
Tasks may be toolchain, a new appliance/application or some preconfigured
sets of packages and configurations as kodi, mpd, firefox and more.
The tasks are limited to a plausible choice of hardware and software.
Deduplicate CPU configuration.
You don't wanna compile Kodi for a H8/300 microcontroller ;)