Default to less verbose output for remove_unknown.bat

Probably for cleanup.bat too.

Although not run often I’ve observed that minimising the cmd window causes both CPU usage & disk activity in resource Monitor filtered by urbackup_srv.exe to rise, suggesting faster execution when not updating that window & scrolling endlessly.

So it occurred to me that only outputting things of interest to mere mortals e.g. "deleting previously marked… ", next actual stage/job, etc & skipping reporting all the link & database updates & deletions unless a /v option were passed would perhaps speed these scripts up for everyone, while maybe leaving an option for the full output by /v for devs & specific troubleshooting.