Clean up files after upload (causes slower startup / errors for uploaders)

[tzarebczan]

Any files that are done uploading can be cleaned up from each SDK's file manager.

If the upload process doesn't rely on the file record, these can probably be cleaned up by a file delete --delete_all command or clearing lbrynet.sqlite on restarts

We've had SDK restarts and when uploaders try to publish, they get an error that the file manager isn't ready because it's still loading much longer (20+ min) vs when the SDK is ready.