ENT-4236 | added chunked_queryset utility.

[HammadAhmadWaqas]

Description:

  Added utity to Slice a queryset into chunks.

  The function slices a queryset into smaller QuerySets containing chunk_size objects and then yields them. It is
  used to avoid memory error when processing huge querysets, and also to avoid database errors due to the
  database pulling the whole table at once. Additionally, without using a chunked queryset, concurrent database
  modification while processing a large table might repeat or skip some entries.

JIRA:

ENT-4236

Dependencies:

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Merge deadline:

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Installation instructions:

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Testing instructions:

1. Open page A
2. Do thing B
3. Expect C to happen
4. If D happened instead - check failed.

Reviewers:

• [ ] tag reviewer

Merge checklist:

• [ ] All reviewers approved
• [ ] CI build is green
• [ ] Version bumped
• [ ] Changelog record added
• [ ] Documentation updated (not only docstrings)
• [ ] Commits are squashed

Post merge:

• [ ] Create a tag
• [ ] Check new version is pushed to PyPi after tag-triggered build is finished.
• [ ] Delete working branch (if not needed anymore)

Author concerns:

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[HammadAhmadWaqas]

@robrap I have incorporated feedback. Could you please review it again?