[SparkyFitness] Integrate equivalent measurements into a single unit variant

## Is your feature request related to a problem? Please describe. I'd rather not have three independent unit variants for the same food. It would be great if instead of having to manually copy nutrients and scroll, we could optionally include multiple variants within the same nutrient data. ## Describe the solution you'd prefer A plus sign to the right of the unit variant, either in place of, or next to the "copy" icon. Clicking it would add another line immediately below the current serving size and unit type, which would allow you to add equivalent unit types. For instance, after entering 100g, you could enter "1 cup" and "4 pieces." A minor benefit to this is if you need to add to the nutrition data later on, you would only have to do this once, not three times.