config: move down companion libraries sub-menu

Move the companion libraries sub-menu down the main menu.
That way, the user does not need to go back and forth in the menu
to change options set by the different components that select the
companion libraries (binutils, gcc, gdb).

source config/global.in

source config/target.in

source config/toolchain.in

source config/kernel.in

source config/binutils.in

source config/cc.in

source config/libc.in

source config/tools.in

source config/debug.in

source config/companion_libs.in