[action] [PR:3138] Add support for ECMP and LAG hash offset (#3138)

[mssonicbld]

• Add support for ECMP and LAG hash offset What I did Add support to update ECMP and LAG hash offset. Orchagent checks for SAI attribute capability and configure the offset values.

Why I did it To avoid ECMP hash imbalance across T0 and T1s, different hash offsets can be configured.

How I verified it sonic-mgmt tests ipfwd/test_nhop_group.py

[mssonicbld]

Original PR: https://github.com/sonic-net/sonic-swss/pull/3138

[mssonicbld]

/azp run Azure.sonic-swss

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[StormLiangMS]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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[StormLiangMS]

/azp run Azure.sonic-swss

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[mssonicbld]

/azp run Azure.sonic-swss

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