Add update checker management command and documentation

[lvb05]

This PR adds a basic update check mechanism for IntelOwl.
It allows to verify whether the running instance is behind the latest published GitHub release.

Included changes

• Added api_app/core/update_checker.py for version fetch + comparison logic
• Added Django management command: check_updates
• Added settings keys (UPDATE_CHECK_URL, version reuse via existing VERSION)
• Updated README with usage + configuration notes

How to use

python manage.py check_updates

The command will:

1. fetch the latest GitHub release tag
2. normalize version strings
3. compare against the locally configured version
4. log whether a new version is available

No version upgrade happens automatically.
Fixes #2876

Notes

• UPDATE_CHECK_URL is now environment configurable
• local version comes from existing VERSION secret setting
• no new dependencies added
• cron / job scheduler usage referenced in docs if periodic checking is desired.

Checklist

• I have read and understood the rules about how to contribute to this project.
• The pull request targets the correct branch.
• This PR is linked to an approved issue (Add update checker #2876).
• A new plugin (analyzer, connector, visualizer, playbook, pivot, or ingestor) was added or modified.
  N/A – this PR does not introduce or modify any plugins.
• No new external libraries were added.
• Linters (Black, Flake8, Isort) report no errors.
• Tests were added or updated.
  N/A – this PR adds a management command and configuration logic only; existing functionality and tests are unaffected.
• Documentation was updated where appropriate (README updated with usage and configuration).
• GUI changes were made.
  N/A – backend-only change.
• I have addressed any CI or linter warnings triggered after submitting the PR.

[fgibertoni]

Hey @lvb05 thanks for your contribution. Can you please compile the checklist in PR template ? It contains many important step to follow before asking for a review.

[lvb05]

Hey @lvb05 thanks for your contribution. Can you please compile the checklist in PR template ? It contains many important step to follow before asking for a review.

I’ve added and completed the PR checklist in the description.
Please let me know if anything needs adjustment. Thanks!

[fgibertoni]

I can tell you've not read it carefully since your PR is pointing to the master branch.
Please read it carefully and adjust accordingly.

[lvb05]

Hi @fgibertoni,
I’ve updated the PR to target the develop branch and fixed the formatting issues.
All checks are green for now.
Thanks for your time!

[fgibertoni]

Hey, thanks for your PR! Looking good overall 😃
Please address the pipeline for errors.

[fgibertoni]

Looking good, thanks!
@mlodic for last check on expected results, otherwise we can merge this.

[mlodic]

can you please show an example output of this command? a screenshot

Also there's no cronjob here but only the management command even if we agreed on that in the issue. This won't be run by the normal user manually, we need something that runs automatically and notify the user.

Also, the cronjob would need to add a notification through the current notification system. In that way, the user would see that notification in the GUI at the top right as a message.

[mlodic]

we cannot pollute the ReadMe with this content. Please remove this line and add this instead with a new PR in the Installation section: https://github.com/intelowlproject/docs/blob/main/docs/IntelOwl/installation.md