change names of external annotation data adapters

[njmmatthieu]

• oncodashkb/adapters/copy_number_alterations.yaml -> oncodashkb/adapters/copy_number_alterations_external.yaml
• oncodashkb/adapters/single_nucleotide_variants.yaml -> oncodashkb/adapters/short_variants_external.yaml
• oncodashkb/adapters/single_nucleotide_variants_local.yaml -> oncodashkb/adapters/short_variants.yaml