BibRank: citation indexer sanity checks and alerts

• Adds sanity checks to the citation indexer. Namely, (a) ignores ill-formed 999C5s values that do not loosely match our journal publication information standard, and (b) warns when a report number of a journal publication information search would give more than one record found. (Previously, the former was silently attempted to match which could give false matches with partial data, and the latter silently took the oldest record ID only in Invenio master, but all record IDs in OPS.) (closes #1091)