additional features for docker container: get sql scripts and config from git, retry feature and sleep after success feature

[kai-dyr]

additional features (helpful e.g. when container is used in kubernetes pod):

• allow container to get sql scripts and config from git
• allow dbmaintain retry in case of error
• feature to sleep forever after success

[kai-dyr]

@remast travis-ci build is failing due to my missing docker credentials. I tested the container in my local kubernetes environment.