this is better design wise as we won't have to keep checking if the
indices have been migrated or not. We'll just check the database version
and do the appropriate migrations based on that.
This should not affect the items or their server representation.
This change is necessary to allow multiple items with same id
that live in different collections.
For example, shortcuts have the same id as the inner reference they
point to. This was not possible before and would cause an overwrite
of the original value.
