Limit requesting prior tasks for ranking in scheduler

[jpbruinsslot]

Changes

Limit requesting prior task in the BoefjeScheduler for ranking. At the moment we don't leverage ranking of tasks based on prior task runs. At least we should limit the number of tasks. This PR will limit this to the last task that has run, since the ranker only uses the last run task at the moment.

QA notes

Nothing really to QA here. We limit the number of tasks we retrieve from the database to make ranking a bit more optimized. Regular running of scanning jobs should continue to work. Mainly rescanning a job that has already been executed can be tested to make sure that it continues to work.

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Code Checklist

• All the commits in this PR are properly PGP-signed and verified.
• This PR only contains functionality relevant to the issue.
• I have written unit tests for the changes or fixes I made.
• I have checked the documentation and made changes where necessary.
• I have performed a self-review of my code and refactored it to the best of my abilities.

• Tickets have been created for newly discovered issues.
• For any non-trivial functionality, I have added integration and/or end-to-end tests.
• I have informed others of any required .env changes files if required and changed the .env-dist accordingly.
• I have included comments in the code to elaborate on what is not self-evident from the code itself, including references to issues and discussions online, or implicit behavior of an interface.

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Checklist for code reviewers:

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Checklist for QA:

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[ammar92]

Nice work. Tiny question, looks good otherwise