Merge changes from topics "deps_base_dir_filesystem", "filesystem_rootdir"

* changes:
  Add rootdir contents to microdroid
  Set base_dir of microdroid to system
tree: 0dbbbf16c7b761cea41379d264a188044b97d264
  1. apex/
  2. authfs/
  3. docs/
  4. microdroid/
  5. tests/
  6. virtmanager/
  7. .clang-format
  8. PREUPLOAD.cfg