- Now using a table to determine sync action

  only after processing their "operation".
  This way we gain idempotency for not-commited changes

  for syncUpload.
  ToDos:
  - Add this to the other sync execution functions
  - Add a throtteling function in order to avoid
    more than N concurrent uploads at the same
    time.
  - Test the conflict cases

  that doesn't allow to remove store items in the
  loop.
  Instead, we'll now record the status of each
  operation and use a filter