Merge changes I6504dc6b,I47c7eac1

* changes:
  Add an executable to create a microdroid signature
  Add a proto for the microdroid signature partition
tree: 65ce9cee85c4000bee4b245b1df5e1fa47e175c8
  1. apex/
  2. authfs/
  3. docs/
  4. microdroid/
  5. tests/
  6. virtmanager/
  7. vm/
  8. .clang-format
  9. PREUPLOAD.cfg