Updated the swagger content - Groups

[shavidissa]

Purpose

Updated the swagger content for adding a device to many groups and adding devices to a group. Further, formatted the swagger content.

Goals

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Approach

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User stories

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Release note

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Documentation

API docs (still being hosted)

Training

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Certification

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Marketing

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Automation tests

• Unit tests

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• Integration tests

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Security checks

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Samples

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Related PRs

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Migrations (if applicable)

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Test environment

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Learning

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