This reverts commit 781320514623653077cda2d910b9baf150949bd1.

I'm doing changes for 20241206 rev8. It was a mistake to
remove these; they will be removed again, after rev8.

The documentation standardised on ./mk a while ago now, and
it's almost time to remove these commands. However, anyone
using the old commands ought to be able to, up to and including
any revision of the Libreboot 20241206 release.

It is my intention that these legacy commands finally be
removed for the next testing release, as part of a much wider
build system audit that I'm doing between now and then.

(Libreboot Build System Audit 7 is underway, and several of
these early audit7 changes are going on 20241206 rev8; after
that, I will create a branch named 20241206_branch off of rev8,
and anything in master from then on will contain much wilder
changes, with more conservative changes in 20241206_branch)

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

We only use ./mk now.

./build still exists for now. This will be removed
in a future revision, when the trees script is removed
and merged with the main script.

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

as opposed to the current 3-level structure.

recent build system simplifications have enabled
this change, thus:

./build fw coreboot -> ./build roms
./build fw grub -> ./build grub
./build fw serprog -> ./build serprog
./update project release -> ./update release
./update project trees -> ./update trees
./update vendor download -> ./vendor download
./update vendor inject -> ./vendor inject

alper criticised that the commands were too long,
so i made them shorter!

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