Create meal products

[pd-dudkiewicz]

meal_product table creation migration
tests
validation
exception handling

• POST /meal-product
  request:
  product_id, date (optional, default to today's date), weight, meal_index
• GET /meal-products with mandatory date query param
• PUT /meal-product/{id}
  request:
  id, weight, meal_index, TBD: product_id
• DELETE /meal-product/{id}