buffet: Update the base packages for commands and state to GCD spec

Updated the base command and state definition in buffet to match the
current GCD spec published at [1] and [2].

[1] https://developers.google.com/cloud-devices/v1/reference/device-api/base/state
[2] https://developers.google.com/cloud-devices/v1/reference/device-api/base/commands

BUG=brillo:805,brillo:807
TEST=FEATURES=test emerge-link buffet

Change-Id: I3f60dae4465bcf6a84c5d220aab6ec2464f64fe6
Reviewed-on: https://chromium-review.googlesource.com/265487
Trybot-Ready: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>