Add new and harden Celestica platforms (sonic-net#18191)

Why I did it
Harden existing Celestica platforms Belgite and Silverstone and add support for new platforms Seastone2, Questone2A, DS4000-v2, DS3000-v2, DS2000-v2
Rename Belgite platform to DS1000.

How I did it
Commit/push Celestica internal hardened changes and rename Belgite platform to DS1000.

How to verify it
Verifed the platform boots fine and all platform CLICK commands excute as expected using actual Celestica HW in all the above mentioned platforms.

Author: jemifdo