Implement missing API tests connected with the subtree of the project for tempest

This BP is to add the missing test-cases connected with operations on a subtree of projects - Enable or disable subtree - Delete subtree

Authentication specific routes tests for tempest

Adding Tempest tests to cover the new V3 API connected with Authentication Specific Routes: 1. Get service catalog (GET /v3/auth/catalog) 2. Get available project scopes (GET /v3/auth/projects) 3. Get available domain scopes (GET /v3/auth/domains)