Handle new splice effects in ensembl-vep version 105

[GFJHogue]

Per https://github.com/Ensembl/ensembl-vep/releases/tag/release%2F105.0 there are 3 new effect terms in VEP that need handling.

• splice_donor_5th_base_variant (SO:0001787)
• splice_donor_region_variant (SO:0002170)
• splice_polypyrimidine_tract_variant (SO:0002169)

I set the priority to match splice_region_variant (see the severity order here: https://useast.ensembl.org/info/genome/variation/prediction/predicted_data.html).