Remove the skin from the turkey and reserve. Carefully cut the bones out and discard them (or freeze for making stock later).
Season the breast all over with salt, sweetener, pepper, onion powder, ginger, and oil. Place the two breast halves on top of each other so that the thick ends are on opposite sides, forming an even roll. Roll tightly and tie with a string every few inches. Add to a sous vide safe bag and refrigerate for 24 hours and up to 3 days.
Just before cooking, add the fresh herbs and garlic. Remove the air using a water displacement method to push the air out (with the bag open, lower the bagged turkey into the water so that the air is slowly pushed out and then seal). Heat a sous vide water bath to 145ºF. Cook for 2 hours 30 minutes and up to 3 hours 30 minutes.
While the turkey cooks, prepare the skin and gravy. For the skin, preheat the oven to 400ºF and line a rimmed baking sheet with parchment paper. Dry the skins well and then spread them flat onto the prepared baking sheet. Season lightly with salt and pepper. Place a second parchment sheet and baking tray over top to keep the skin flat as it cooks. Bake for 30-45 minutes, or until golden and crisp. Set onto paper towels to remove excess fat. Break into bite size pieces. (Can be made up to 3 days ahead, refrigerated, and reheated in a 400ºF oven fr a couple of minutes to re-crisp).