live data for network and cores

[clearloop]

on importing blocks, we need to record the author (validator) and cores used to our database, the data will be used in

1. the core dashboard in /
2. and the validators map in /network

query Live {
    slot 
    authors
    cores
}

for supporting the /network dashboard, we need a common query for validators state on epochs

query Validators(epoch) {
     validators # a list of validators' bandersnatch pub key via the order of authoring blocks, safrole / fallback
}