Unify taxon aggregate handling

[mikkohei13]

As FinBIF data user, I want that taxon aggregates are handled systematically, so that data is easy to use.

• Standardize taxon ranks. Currently multiple ranks correspond to a taxon aggregate: "group", "aggregate", "speciesAggregate", etc.
• Standardize suffixes. Currently we have suffixes "coll", "group", "-group", "-type", "complex", "sensu lato", "-ryhmä", "sec.", "s.l.", "-ryhmä s. lat.", maybe more.
• iNaturalist species complexes are linked to taxon aggregates

Discussion: https://luomus-ict.slack.com/archives/CJNSPRUS1/p1787304999583489