Massive refactoring of external header files.

This reduces the number of exported header files to the minimum needed by
the existing userspace utilities and firmware implementations.

BUG=chromium:221544
BRANCH=none
TEST=manual, trybots
CQ-DEPEND=CL:47019,CL:47022,CL:47023

  sudo FEATURES=test emerge vboot_reference
  FEATURES=test emerge-$BOARD \
                vboot_reference \
                chromeos-cryptohome \
                chromeos-installer \
                chromeos-u-boot \
                peach-u-boot \
                depthcharge

Change-Id: I2946cc2dbaf5459a6c5eca92ca57d546498e6d85
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/47021
Reviewed-by: Randall Spangler <rspangler@chromium.org>
137 files changed