William Mo

### Issue description In this https://github.com/apache/apisix-dashboard/blob/master/api/conf/conf.yaml line 78 -81 the dashboard authentication use plain text in the configuration. it would cause the security risk for auditing is there any way...

I am not sure if it is related to my Docker environment, but for this command: docker build -t mattermost-integration-gitlab . I need to update to "docker build -