Add more metrics to understand several keypoints

Simple metrics that will help deciding what to do for upcomings quarters. A complete refactoring of metrics will be planned on Q1 2021.

• HTTP/HTTPS metrics are needed in order to let us know if we can tackle NXDRIVE-1917.
• Metrics on the NuxeoDrive.GetChangesSummary call time are needed in order to understand what needs to be priorized for NXDRIVE-595.
• Direct Transfer: metrics for duplicates import to acknowledge the current situation.
• S3 or Nuxeo metrics for uploads.
• Sync error metrics.
• Sync on Windows when read-only is not satisfied locally.
• Account count metrics in order to priorize NXDRIVE-2296.