standardize names below species level (eliminate var, subsp, etc.)

[LunaSare]

It is not implemented in datelife yet, so we drop names under the species level.
This happens during the taxonomy standardization step:
We call rotl::tnrs_match_names() inside datelife::input_tnrs()

Look at rphylotastic::taxa_resolve_names_with_gnr(), might already do what we need.