This PR adds a small check if the VSS provider fails to initialize. We already checked if the user appears to have the `SeBackup` privilege and tailor the message to that.
With this PR we now also factor in a potentially missing VC Redist package, such that the user is informed about this package not being found.
The intention is to point towards the most likely cause of the failure. If VSS works, or not running on Windows, nothing has changed.
This refactors a part of the database and adds a new "sync" command that reuses a lot of the backup logic to take a set of sources and apply them to a backend.
Unlike the backup process, the sync copies files verbatim without any encryption.
Kenneth Skovhede