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
```
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