OAuth request/access token and consumer support for oauth client API

Add support for creating request and access tokens,
and to authorize request tokens. Also adding basic CRUD for
consumer entities.

DocImpact
Change-Id: Ib9d0b223f202a7e33cbad1602da5be7479cd3284
implements: bp add-oauth-support
Merge "OAuth request/access token and consumer support for oauth client API"