Added new Trident API Keystore interface

A new VAR_TRIDENT_API object API now exists for decoupled keystore
interfacing;  It can work against legacy indexeddb as well as user
provided web services, using common API.  Old tridentdb API_ functions
still work but you should probably use/learn the new VAR_TRIDENT_API
methods for future-proofing (see apireference).