Extend `sync_from` and `sync_to` to accept an existing diff

[dgarros]

Environment

• DiffSync version: 1.3.0

Proposed Functionality

Currently doing a diff_to/from followed by a sync_to/from, result in calculating the diff twice because sync_to/from are calculating a new diff automatically.
The proposal is to extend sync_from and sync_to to accept an existing diff

    self.log_info(message="Loading current data from Data Source...")
    diffsync1 = DataSourceDiffSync(job=self, sync=self.sync)
    diffsync1.load()

    self.log_info(message="Loading current data from Nautobot...")
    diffsync2 = NautobotDiffSync(job=self, sync=self.sync)
    diffsync2.load()

    diffsync_flags = DiffSyncFlags.CONTINUE_ON_FAILURE

    self.log_info(message="Calculating diffs...")
    diff = diffsync1.diff_to(diffsync_1, flags=diffsync_flags)

    if not self.kwargs["dry_run"]:
        self.log_info(message="Syncing from Data Source to Nautobot...")
        diffsync1.sync_to(diffsync2, flags=diffsync_flags, diff=diff). <<<<<<<<<<<
        self.log_info(message="Sync complete")

Use Case

Performance improvement, there is no need to calculate the diff twice on the same dataset