Client Payment Cards
Client Payment Cards — 5 endpoints.
List a client's active saved cards
GET /clients/clientId/cards
Save a new card the client tokenized via Hosted Fields
POST /clients/clientId/cards
Mint a Hosted-Fields handshake to add a new card
POST /clients/clientId/cards/handshake
Set a card as the client's default (pre-selected on charge)
POST /clients/clientId/cards/tokenId/default
Remove (soft-revoke) a saved card
DELETE /clients/clientId/cards/tokenId

