Support pure refseq inputs in VUStruct

[ChrisMoth]

Per ChatGPT, this format should be easy to integrate:

Example:

vep
--species homo_sapiens
--assembly GRCh38
--refseq
--hgvs
--symbol
--mane
--input_data "NM_000546.6:c.215C>G"
--format hgvs

That variant is the classic TP53 codon 72 polymorphism. VEP should return something conceptually like:

Uploaded_variation Feature Consequence HGVSc HGVSp
NM_000546.6:c.215C>G ENST00000269305.9 missense_variant NM_000546.6:c.215C>G NP_000537.3: