unify build/defconfig and modify/defconfig

they fundamentally perform the same action: copy
the .config file and run make, but build runs
make-all, while modify runs make-oldconfig or
make-menuconfig

merge this functionality together

also:
./handle config file

^ this is the new syntax, not:
./build defconfig for

for example:

./handle config file -b coreboot x200_8mb <-- build x200 rom
./handle config file -m coreboot x200_8mb <-- modify configs
./handle config file -u coreboot x200_8mb <-- make-oldconfig
./handle config file -u seabios
./handle config file -b u-boot

yes, 1 script and a sloccount reduction of 52. and the audit?
it continues.

Signed-off-by: Leah Rowe <leah@libreboot.org>

handle

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+lbmk