Add merge / replace for netmiko dispatcher

[jeffkala]

something like

    @classmethod
    def merge_config(
        cls,
        task: Task,
        logger,
        obj,
        config: str,
    ) -> Result:
        """Send configuration to merge on the device.

        Args:
            task (Task): Nornir Task.
            logger (logging.Logger): Logger that may be a Nautobot Jobs or Python logger.
            obj (Device): A Nautobot Device Django ORM object instance.
            config (str): The config set.

        Raises:
            NornirNautobotException: Authentication error.
            NornirNautobotException: Timeout error.
            NornirNautobotException: Other exception.

        Returns:
            Result: Nornir Result object with a dict as a result containing what changed and the result of the push.
        """
        logger.info("Config merge via netmiko starting", extra={"object": obj})
        # Sending None to napalm_configure for revert_in will disable it, so we don't want a default value.

        try:
            push_result = task.run(
                task=netmiko_send_config,
                config_commands=config.splitlines(),
                enable=True,
            )
        except NornirSubTaskError as exc:
            error_msg = f"`E1015:` Failed with an unknown issue. `{exc.result.exception}`"
            logger.error(error_msg, extra={"object": obj})
            raise NornirNautobotException(error_msg)

        logger.info(
            f"result: {push_result[0].result}, changed: {push_result.changed}",
            extra={"object": obj},
        )

        if push_result.diff:
            logger.info(f"Diff:\n```\n_{push_result.diff}\n```", extra={"object": obj})

        logger.info("Config merge ended", extra={"object": obj})
        return Result(
            host=task.host,
            result={"changed": push_result.changed, "result": push_result[0].result},
        )