FingerprintCleanupThread may delete fingerprints if there is no references to jobs.

• [DECLINED] For old cores it is required to create an artificial project, which would reference builds on-demand. Such project would also allow to manage fingerprints from its interface.
• We should add an extension point, which would allow to prohibit the Fingerprint deletion

Old discussion summary:

• Container fingerprints are not protected from fingerprint cleanup by the core due to the missing build references
• I've never seen the Traceability fingerprints cleanup, but it may happen according to the Jenkins core code
• FingerprintsCleanupThread should run randomly with one day interval according to the code