HGVS expression validation: Handle new VV warning

[ifokkema]

VV included a new warning for variants that are described on the wrong side of the intron:
openvar/variantValidator#518

Make sure our libraries interpret these correctly; currently, our VV interface library seems to fail hard on these.
Example input:
NC_000016.10(NM_000086.2):c.791-802_1056+1445del

[ifokkema]

This is fixed by the new VV library, integrated into the new HGVS library. This new library needs to be integrated into LOVD3.