Enable platform user to create a customizable build-container

[xiabai84]

At a lots of companies build-jobs were run inside of company internal network cause diverse security issues, from there the build-container won't be able to access to internet to pull the dependencies from outside.

Some of them build a company proxy with JFrog-Artifactory, which can filter, validate and redirect requests to the outside.
For such case is necessary to enable ks-users to build their own BuildContainer based on their company's network and security settings, credentials etc..

The current devops-agents are all build from opensource contributors, which can't cover all customer's needs. Further on, the maintenance for such containers could be also expensive and not scalable.

My suggestions:

1. Provide user some common build-container like maven, python, nodejs with basic settings.
2. Provide a template build-container, which give user the opportunity to develop on their own needs.