`inventory` table: remove `model`, `serial`, `partNum` from keys

[LucaNicosia]

Test inclusion requirements

In case the PR contains an enhancement or a new platform/service support, some tests have to be added for the new functionality:

• any fix or enhancement SHOULD include relevant new tests or test updates, if any tests need updating.
• a new platform support MUST include the relevant input files similar to what we have in tests/integration/sqcmds/-input directories, along with the relevant tests in the tests/integration/sqcmds/-samples dir. That list MUST include the all.yml file fully filled out.
• any new service (or table) addition MUST include comments about what network OS are supported (along with version) with this command along with test samples for those platforms and input files in the *-input dir

For additional information about tests, follow this link

Related Issue

Fixes #

Description

The model, serial and partNum columns should not be keys of the inventory table

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

New Behavior

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Contrast to Current Behavior

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Discussion: Benefits and Drawbacks

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Changes to the Documentation

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Proposed Release Note Entry

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Comments

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• [x] I have read the comments and followed the CONTRIBUTING.md.
• [x] I have explained my PR according to the information in the comments or in a linked issue.
• [x] My PR source branch is created from the develop branch.
• [x] My PR targets the develop branch.
• [x] All my commits have --signoff applied