Merge remote-tracking branch 'nthykier/auto-decruft' into merge

Merge remote-tracking branch 'nthykier/auto-decruft' into merge

* nthykier/auto-decruft:
  Rewrite auto-decruft to group removals
  daklib/rm: Add a fitting dak-quote
  auto-decruft: Batch check source-less cruft
  auto-decruft: Fix wording of removal message
  auto-decruft: Use bind variables
  auto_decruft: Fix typo
  utils: Use a set rather than list
  utils: Drop unused fields from database query
  utils: Avoid some throw away collections
  generate_filelist.py: Fix typo
  utils: Add a quiet=False parameter to check_reverse_depends
  Add dak auto-decruft command based on cruft-report
  Move two queries from cruft_report to daklib/cruft
  Extract a "remove" method from "dak rm"