Integrated customizable bash prompt

Get a nice configurable shell prompt for all nodes... YEAH!
This is a followup pull request after discussion on https://github.com/crowbar/barclamp-deployer/pull/219
```ruby
j = JSON.parse(File.read("chef/data_bags/crowbar/bc-template-provisioner.json"))
j['attributes']['provisioner']['default_password_hash']
# results in "$1$BDC3UwFr$/VqOWN1Wi6oM0jiMOjaPb."
```

So everything is fine, it's correct escaping.