Support docker image proxy pull in Supervisor

[choonho]

Plugin image is located at docker repository.

Some environment can not pull image from docker repository. Let's support proxy image pull like harbor.

Assumption

• repository base url is changed
• image path is same

Example

• (original) hub.docker.com/spaceone/plugin-aws-cloudservice
• (updated) harbor.proxy.local/spaceone/plugin-aws-cloudservice