Merge bash scripts

There could be some nitpicking on output, so here it is :smile::
```console
$ ./bashbrew/build.sh --namespaces=yosifkit hello-world
Processing hello-world:latest ...
$ ./bashbrew/push.sh --namespaces=yosifkit hello-world
Processing hello-world:latest ...
Pushing yosifkit/hello-world:latest...

$ ./bashbrew/build.sh --namespaces=yosifkit hello-world --no-build
Processing hello-world:latest ...
$ ./bashbrew/push.sh --namespaces=yosifkit hello-world --no-push
Processing hello-world:latest ...
docker push yosifkit/hello-world:latest
```
Ah, they're all sorted that way, not with help being special.  I'll update. :+1: