Suggestion - Add "Skipped" status when a file already exist in the dest. directory

[Larsene]

Add "Skipped" status when a file already exist in the dest. directory.

So we know if a file exist already, that it has not been download again or replaced.

[e-alfred]

This was implemented by @vijaydwivedics, but it requires changes to core Nextcloud files which is not feasible for release at the moment: https://github.com/vijaydwivedics/flowupload-nextcloud-v15

If somebody has a solution that can be packaged into a release I would appreciate that.