Jeversmann/kochiku yml updates

Changes build enqueueing logic so that test command, on success script, and log file targets from kochiku.yml. I also moved the logic for interacting with the GitRepos around to eliminate cases where methods were making assumptions about how they were being called.
now that we are not checking the return value of `update_all`, it makes sense to change this to a standard update.
```
update!(promoted: true)
```