use `obsolete_ICNs` in affiliation normalization and linking

[michamos]

following #323, we need to adapt the affiliation normalization and affiliation linking code to use obsolete_ICNs in addition to legacy_ICN. Those processes should search also in obsolete_ICNs and assign the record where it is found.The end result is that the Literature record will only contain affiliation values based on the legacy_ICN of that record and point to that record as a ref.

[michamos]

Update: this is not urgent, we can postpone this until we want to start migrating Literature to the new scheme