fix: #3637144 Break stale content locks on edit

Stale content locks never expire: Varbase Core's content_lock.settings.yml has no timeout, so it overwrites Content Lock 3's default with NULL.

Issue: https://www.drupal.org/i/3637144

• Add timeout: 1800 to config/optional/content_lock.settings.yml.
• Stop installing the deprecated Content Lock Timeout, drop its settings and Ultimate Cron job.
• varbase_core_update_100003 sets the timeout to 1800 when empty and uninstalls Content Lock Timeout when enabled.

Local pipeline did not run: gitlab-ci-local failed parsing the config (stage:test not found for secret_detection), before any job and unrelated to this change. Gated on the remote pipeline, which passed: https://git.drupalcode.org/project/varbase_core/-/pipelines/1042102

Remaining

• Run drush updb on an existing site, and a fresh install.
• Confirm re-enabling expiry is fine for sites that cleared the timeout on purpose.

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