* make it work even for drafts that have been published before
* also extract a few pieces into utility functions

* because reindexing has been implemented in the core modules for a long
  time now

* because the 'rdm-records rebuild-index' command doesn't rebuild
  indices for all available/required services (at the moment)

* previously, adding files to drafts could fail if the configured limits
  (max. file size, and bucket quota) were too small for the files
* however, the main use for these CLI commands is to ingest files that
  are too large for self-upload via UI or API

* rename old 'orphans' subcommand for files to 'zombies'
* add new 'orphans' subcommand for files that operates on FileInstances
  which don't have any related ObjectVersions anymore

* use f-strings everywhere
* print error messages in yellow to stderr