How to upgrade IndexedDB data for settings?

[ChocolateLoverRaj]

Settings need a way of updating their data.

[ChocolateLoverRaj]

Every setting has its own version number and function for upgrading. Since all settings are part of the same db, they need a version number for the store, which will be the sum of all the version numbers of the settings. New settings can start with the number 0, because they don't need an upgrade. There will be a store with the version numbers of every setting.

[ChocolateLoverRaj]

There is just one version number for the settings IndexedDB. On upgrade, the upgrade functions of very saved setting is called.