So that our user can start leveraging helmfile without too much confusion.
Includes two things:
- A "getting started" guide
- A basic description of the `sync` subcommand
This is important for deployments where the chart repo is protected by client cert validation.
helmfile.yaml is extended to support `certFile` and `keyFile`:
```
repositories:
- name: roboll
url: http://roboll.io/charts
certFile: optional_client_cert
keyFile: optional_client_key
```
Everything works the same if you don't provide values for them.
Regarding the implementation, the "helm repo add" command already supports the cert-file and key-file values, so we just have to pass them through.