Cleanup old builds

[mischnic]

• cleanup old build (more than 10 and older than 14 days) (remove files, keep status, option for rebuild on web)
• commit status
• value for description in status

Show status for every commit: https://developer.github.com/v3/repos/statuses/
and for pull requests

https://developer.github.com/v3/guides/building-a-ci-server/
https://github.com/github/platform-samples/tree/master/api/ruby/building-a-ci-server

Deployment:

https://developer.github.com/v3/repos/deployments/
https://developer.github.com/v3/guides/delivering-deployments/