feat: implement helm installer

[ricardomaraschini]

Don't get desperate, I went through the source code and made some changes:

1. We are downloading admin-console from replicated registry.
2. We install the helm chart as soon as the kubernetes API reports ok.
3. I have removed everything regarding k3s.
4. K0s default config file is not embed as yaml for easier change.
5. I have simplified the "cli/commands" we have to keep them as short as possible (I don't like the idea of Running Options).
6. K0s configuration file is also stored under /var/lib/replicated.