Rethink where/when/how to declare a record citable

[david-caro]

Right now there's a small bit of logic in the builder that decides if the record is citable or not (can be overriden if need be) but maybe that's not the place or the way to set that flag. Maybe using a periodic bibcheck task, and/or moving the check to a standalone function that's dynamically called or something.

[kaplun]

Indeed would be nice to hear from @inspirehep/inspire-content what is the current definition of citeable and whether this should be rethought nowadays.