Maint/burgundy/introduce query v3

    Introduce v3 query API endpoints
    
    This commit introduces the v3 query endpoints.  For now, they are
    all simply routing directly to the v2 endpoints; this commit is
    merely scaffolding.
    
    It also deprecates the v1 endpoints and introduces tests to
    validate the deprecation warnings, and updates all acceptance tests
    to use the new v3 endpoints.