libweave: Remove unnecessary code from base lib

Mostly strings, logs and command line routines.

BUG=brillo:1256
TEST=`FEATURES=test emerge-gizmo libweave buffet`

Change-Id: I69cf44792ee1277109ca1a4b5995c5021d84d434
Reviewed-on: https://chromium-review.googlesource.com/294173
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>