Signature: unit -> Task<StoredPreferenceInfo option> Modifiers: abstract
Get the user preferences of a specific user, returns None when the user never saved anything, the bool indicates whether 'archiving method preferences' where set.
Save the user preferences of a specific user, returns None when the user never saved anything
Set the default preferences for all items (expire, otrmode, savemode). None deletes this preferences and uses the default next time!