Create a minimum framework for testing Jenkinsfile Runner

We need a simple test framework to verify that Jenkinsfile Runner images can run at all.

• Create a shunit2/bats test framework for verifying Jenkinsfile Runner Docker images
• The framework takes Jenkinsfile from a directory and runs against the image. Then it waits for completion
• Once the execution is completed, there are hooks which can verify log outputs and return result
• There is a timeout support