Gazoo-device

Added examples of package exports for every possible extension to CONTRIBUTING.md.

Bug fixes:
- Fixed adb_utils.get_adb_devices failures when any device is reported as "offline".

Features:
- Extension packages can now extend GDM with CLI commands. See https://github.com/google/gazoo-device/blob/master/CONTRIBUTING.md#adding-a-new-cli-command.

Bug fixes and improvements:
- Fixed handling of DeviceErrors in mobly_controller.get_info during property retrieval.
- Added adb_utils.fastboot_check_is_unlocked for checking if a fastboot device is unlocked.

Unit tests:
- Added a unit test for PwHdlcRpcClient module.
- Refactored and increased unit test coverage for Pigweed RPC transport.
- Increased unit test coverage for Matter device classes.
- Open-source package_registrar unit tests.
- Open-sourced CLI unit tests.
- Open-sourced Pigweed RPC and JLink flash capability unit tests.

Added support for Matter dev board detection on MacOS hosts.

- Added collection of multiple device properties to Mobly integration get_info() method.
- Added Apache license header to embedded_script_dli_powerswitch_test.py.

- Added reboot, factory_reset, firmware_version methods and properties to ESP32 Matter locking app controller.
- Added a capability to run and stop embedded scripts on DLI power switch devices.