CTA Frontend should reject files with owner_uid=0

CTA explicitly blocks archival of files without an owner.

Currently, if owner_uid=0, the file is successfully archived, and only during reporting is the error reported:

Jan 5 17:34:15.401517 gmv18017 cta-taped: LVL="**INFO**" PID="30037" TID="30096" MSG="In cta::ArchiveMount::reportJobsBatchTransferred(), archive job successful." thread="MainThread" tapeDrive="LTO8D0" mountId="234" tapeVid="FL0378" mountType="ARCHIVE_FOR_USER" fileId="4294967330" type="ReportSuccessful"
Jan 5 17:34:15.425767 gmv18017 cta-taped: LVL="**ERROR**" PID="30037" TID="30096" MSG="In ArchiveMount::reportJobsBatchWritten(): got an exception" thread="MainThread" tapeDrive="LTO8D0" mountId="234" exceptionMessageValue="filesWrittenToTape: filesWrittenToTape failed: TapeFileWrittenEvent is invalid: diskFileOwnerUid is 0"

This should be detected at a much earlier stage, in the CTA Frontend, before the job is queued for archival.