Re-land: releasetools: Deprecate GKI build rules

(Re-land of Ie882fccd864920289e48366e99a4ebd67e784d0d)

We no longer build GKIs from the platform tree.
These build commands were neither used nor maintained anymore, so clean
them up to reduce maintenance effort.
Keep the command line options as no-op, so existing scripts that still
specifies the deprecated options don't break.

Bug: 229701033
Test: presubmit
Change-Id: I0f7d05562dbc3eed29e902d6dc9a0f2e4083aaa6