fix(controller): Use correct entrypoint for run

Running commands in an image build using git push requires to use ‘/runner/init’ as entrypoint, otherwise environment variables inject by buildpacks are missing.

Fixes #1801, fixes #1568
That would mean that we'd be running `bash -c -c`, but it seems Jenkins passed it. Also seems to work locally:

```
><> bash -c -c 'echo hi'
hi
```

Strange behaviour, but works nonetheless.