Merge change 22354 into donut

* changes:
  docs only. add donut image for homepage announcement.
tree: 0f9e145af87099f5df716210c3edbe2b5cdf8820
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh