Implemented uploading prefetto trace output to perfetto web UI.

This involved introducing open_ui.py, which contains
the new HttpHandler class and open_trace method,
integrating open_trace into command_executor.py, and
updating Android.bp accordingly. Finally, added one
unit test to tests/command_executor_unit_test.py.

Test: atest_command_executor_unit_test
Bug: 355053544

Change-Id: Iff1b6ddd47e4889107b44226e967c369ad6b267f
4 files changed