Resource scores

Any resource should have "score" modifiable by user, which can be used in sortings.
This score must be implemented as separate table `.ark/scores` and bind resource id to an integer number.

Start by tracing how resources are stored and how sorting is implemented; the issue specifies a separate `.ark/scores` table. Done means users can modify an integer score bound to each resource id and use that score in resource sorting.

Written by the indexing model from the issue text.