Fix directionality

[ahwagner]

The following sources need to have their evidence directionality (association.response_type.keyword) updated.

OncoKB:
Loaded with "N/A". All associations are predictive of response unless otherwise indicated. See http://oncokb.org/#/levels for details.

CIViC:
Need to prepend the evidence_direction field to evidence_type, e.g. Supports Sensitivity instead of Sensitivity. Also, for clarity, we should map positive and negative to positive outcome and negative outcome.

MolecularMatch:
Looks like it's using the evidence level. Should be using the responseType value.

Jax-CKB and CGI look good. PMKB is all N/A, but it appears that these data are unavailable, so there's nothing to do about it.