Add candidate info to OccupiedCore (#2134)

* guide: add candidate information to OccupiedCore

* add descriptor and hash to occupied core type

* guide: add candidate hash to inclusion

* runtime: return candidate info in core state

* bitfield signing: stop querying runtime as much

* minimize going to runtime in availability distribution

* fix availability distribution tests

* guide: remove para ID from Occupied core

* get all crates compiling