Use std::filesystem for reading directory in apexd

Bug: 124359798
Test: 1. atest apexservice_test
      2. atest apex_file_test
Change-Id: I990dcc34c374dd9f2e95ce980790ec42f902c728
4 files changed
tree: 007767a2756f3b6870d26e5d666b904d444b5e5b
  1. apexd/
  2. apexer/
  3. proto/
  4. shim/
  5. tests/
  6. OWNERS
  7. PREUPLOAD.cfg