Why I did it
Fix the following issues for Seastone platform:
- system-health issue: show system-health detail will not complete #9530, Celestica Seastone DX010-C32: show system-health detail fails with 'Chassis' object has no attribute 'initizalize_system_led' #11322
- show platform firmware updates issue: Celestica Seastone DX010-C32: show platform firmware updates #11317
- other platform optimization
How I did it
Modify and optimize the platform implememtation.
How to verify it
Manual run the test commands described in these issues.
**- Why I did it**
- To fix failed test cases of Seastone-DX010 platform APIs that found on [platform_tests](https://github.com/Azure/sonic-mgmt/tree/master/tests/platform_tests/api) script
**- How I did it**
1. Add device/celestica/x86_64-cel_seastone-r0/platform.json
2. Update functions to support python3.7
3. Add more functions follow latest sonic_platform_base
4. Fix the bug
