Part of lp.scripts.garbo View In Hierarchy
A BulkPruner to remove old `LiveFSFile`s. We remove binary files attached to `LiveFSBuild`s that are more than `LiveFS.keep_binary_files_interval` old and that are not set as base images for a `DistroArchSeries`; these files are very large and are only useful for builds in progress. DAS base images are excluded because `DistroArchSeries.setChrootFromBuild` takes a `LiveFSBuild` and we want to have the option of reverting to a previous base image shortly after upgrading to a newer one. Text files are typically small (<1MiB) and useful for retrospective analysis, so we preserve those indefinitely.