Use at most one parallel job in WebDAV sync
requested to merge 441-workaround-for-remote-server-connection-close-when-syncing-to-webdav into development
This is to check if this mitigates the problem a user has reported. If this is the case, we need to implement proper handling for this, e.g. either make the number of workers configurable or catch the remote-host closed error and react to it, by running the next sync with fewer workers.
Closes #441 (closed)