As part of consolidating all common Python-based functionality into the new sonic-py-common package, this pull request:
1. Redirects all Python applications/scripts in sonic-buildimage repo which previously imported sonic_device_util or sonic_daemon_base to instead import sonic-py-common, which was added to the 201911 branch in https://github.com/Azure/sonic-buildimage/pull/5063
2. Replaces all calls to `sonic_device_util.get_platform_info()` to instead call `sonic_py_common.get_platform()` and removes any calls to `sonic_device_util.get_machine_info()` which are no longer necessary (i.e., those which were only used to pass the results to `sonic_device_util.get_platform_info()`.
3. Removes unused imports to the now-deprecated sonic-daemon-base package and sonic_device_util.py module
This is a step toward resolving https://github.com/Azure/sonic-buildimage/issues/4999
Align SFP key names with new standard defined in https://github.com/Azure/sonic-platform-common/pull/97
- hardwarerev -> hardware_rev
- serialnum -> serial
- manufacturename -> manufacturer
- modelname -> model
- Connector -> connector
