builder_config: Cleanup deprecated fields.

Remove deprecated fields from BuilderConfig.Build.
Start renaming install_packages_conf to install_packages.

BUG=chromium:1038975
TEST=generate.sh

Change-Id: I39ad148ef62b9a193ce47bbff88ec863220e9485
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2032438
Reviewed-by: David Burger <dburger@chromium.org>
Commit-Queue: LaMont Jones <lamontjones@chromium.org>
Tested-by: LaMont Jones <lamontjones@chromium.org>
3 files changed