Signed-off-by: maipbui <maibui@microsoft.com>
#### Why I did it
`subprocess.Popen()` and `subprocess.run()` is used with `shell=True`, which is very dangerous for shell injection.
`os` - not secure against maliciously constructed input and dangerous if used to evaluate dynamic content
#### How I did it
Replace `os` by `subprocess`
Remove unused functions
Add support for Accton as9726-32d platform
This pull request is based on as9716-32d, so I reference as9716-32d to create new model: as9726-32d.
This module do not need led driver to control led, FPGA can handle it.
I also implement API2.0(sonic_platform) for this model, CPLD driver, PSU driver, Fan driver to control these HW behavior.