Resolve DRUP-317 "Files attachments"

Paulrequested to merge
DRUP-317-files-attachments into 8.x-9.x

Closes DRUP-317:

  1. Updated ExtendedTranslatorPluginInterface, addded isAttachmentReadyForDownload, downloadAttachmentTranslation and getAttachmentFileName methods.
  2. Refactoring: fixed BaseTmgmtActionApproveForm.php error for PHP 8.3.
  3. DownloadTmgmtActionApproveForm downloads file attachments as well if any.
  4. JobDownload supports downloading attachment translations as well as regular translations.
  5. Introduced FlowScheduler service for simplifying working with TES.

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