Implement different data persisting strategy

[WendtOle]

Currently the data is stored in the local storage.

Disadvantage:

• the data is in exact one browser and in one device
• if the local storage would be cleared all data would be lost Advantage:
• easy to use and not setup or login is required

Advantages of moving to other solution would be that on the same account can be accessed by different devices.

Ideas:

• google drive sheet as backend