Implement trust in identity v3 api
Implement trust in identity v3 api

Added new module in identity v3 api to handle create, read, and delete
operations of trust resources.

Co-Authored-By: Lance Bragstad <lbragstad@gmail.com>
Co-Authored-By: Steve Martinelli <stevemar@ca.ibm.com>

Closes-Bug: #1413718
Change-Id: I2b360b141ff70d4f396466abede859a3db6644f4

dtroyer/osc-lib