feat: GPTQv2 enablement for fms_mo

[bayo-ibm]

Description of the change

This enables GPTQv2 for fms_mo

1. Added new gptq arguments
2. Changed the Readme file for the GPTQ example to reflect the changes

Related issues or PRs

NA

How to verify the PR

Was the PR tested

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• I have ensured all unit tests pass

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[chichun-charlie-liu]

in addition to adding 2 new args to trigger gptqv2, can we also add a simpler option, which allows a new quant_method, i.e. gptqv2, and the rest will be taken care automatically. feels like it would be more user-friendly this way...

[chichun-charlie-liu]

plz check pylint errors