Make queue item expiration configurable via Java system property

[daniel-beck]

Related to https://issues.jenkins.io/browse/JENKINS-26228, https://issues.jenkins.io/browse/JENKINS-31039.

The cache we use doesn't seem to allow for a guaranteed minimum duration without allowing infinite growth, but tunable settings seem like a start (and in the future, increase defaults). I chose 10k as the max size to support busy instances without allowing them to go oom too easily, but this value is a wild guess. Even significant increases in duration seem to be the primary reason for cache eviction.

For now for the PR build and to allow feedback on approach.

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See JENKINS-XXXXX.

Testing done

Ran java -Dhudson.model.Queue.LEFT_ITEMS_CACHE_EXPIRATION_SECONDS=20 -jar jenkins.war and confirmed items disappeared (/queue/item/NN/ 404) ~20 seconds after becoming LeftItems.

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