1. Add basic authorizer for registry which modify the request
to add basic authorization header to request based on configuration.
2. Set basic auth header for proxy when accessing registry
3. Switche the registry to use basic auth by default and use the basic
authorizer to access Harbor.
4. Make necessary change to test cases, particularly
"test_robot_account.py" and "docker_api.py", because the error is
changed after siwtched to basic auth from token auth. #10604 is opened
to track the follow up work.
Signed-off-by: Daniel Jiang <jiangd@vmware.com>
