All detected features and namespaces under the context of Layer and
Ancestry will now have the detectors associated, so that the API can
provide the detection information to the Client.
As one of the steps to simplifies the codebase, the AncestryWithContent
struct is renamed to Ancestry, and Ancestry is removed. It will cause
the PostAncestry request to be slower.
This change pulls as much pagination logic out of the database
implementation as possible. Database implementations should now be able
to marshal whatever state they need into opaque tokens with the
utilities in the pagination package.
Main Clair logic is changed in worker, updater, notifier for better adapting
ancestry schema. Extensions are updated with the new model and feature lister
and namespace detector drivers are able to specify the specific listers and
detectors used to process layer's content. InRange and GetFixedIn interfaces
are added to Version format for adapting ranged affected features and next
available fixed in in the future. Tests for worker, updater and extensions
are fixed.
