Add new product by barcode scan

[dissolution2]

Add function new product to List {

1. scan by user
2. check if product is known to user (Realtime db) true/false
3. true - Add the product amount++
4. false - check Master DB if product is known (Firebase cloud) true/fasle
5. true - Add the proudct to user(realtime db) new Product In the right List
6. false - Add the product to user(Firebase cloud) and user(Realtime db)
7. DM - Check and move Product from user(Firebase Cloud) to Master DB(Firebase cloud) if ok -- if not DM - might have to manually change the data.

[dissolution2]

8. Must allso check user_db for dupplication of products.

[dissolution2]

Done so far:

1. Add product via bareCode to shoppinglist main -Searching through all storage list if product known it is added.

ToDo:

1. if not known, search on main_product_db, if known add it to list.
2. if not known, add by user to user_product_db