Add CI tasks that can be run in a Docker container

Enables a Docker based build server to create logsearch dev releases using a command like:

```
docker build -t $JOB_NAME $(pwd)

docker run -e BOSH_TARGET=https://xx.yy.zz.bb:25555 -e BOSH_USER=sudobot -e BOSH_PASSWORD=$SUDOBOT_BOSH_PASSWORD -v $(pwd):/workspace -t $JOB_NAME rake dev_release:create_and_upload_and_deploy
```

If would be awesome if we could use a pre-populated config/dev.yml and run with -n to get

`logsearch.{ENV['BUILD_NUMBER']}-dev` (or something similar that links the build to the dev release

Could one of you submit a commit that makes that work?