automation: clean up user-visible output

For add_variant_to_yaml.sh, create_coreboot_config.sh, and
create_initial_ec_image.sh:
* Remove messages that tell the user what to do, because the top-level
program that invokes this script will handle those commands, and so
this script telling the user what to do is noise (and possibly harmful)
* Add more information to the commit message that the script prepares
for the user.
* Bump script version number.

Add comments to add_variant_to_yaml.sh as to why we aren't testing the
build as part of the script.

BUG=b:140261109
TEST=n/a

Change-Id: Ic4a61d4d45bde9313b036bdb7b7be2a5879ca925
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/1960055
Tested-by: Paul Fagerburg <pfagerburg@chromium.org>
Auto-Submit: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
Commit-Queue: Paul Fagerburg <pfagerburg@chromium.org>
3 files changed