Vultr API is being inconsisten in what it returns. An empty list when no
resources exists, but a dict of dict when they do. The case needs to be
handled so the module do not fail. An extra test has been added.
This commit introduces a new module called vr_startup_script_facts.
This module aims to return the list of startup scripts avaiable
avaiable in Vultr.
Sample available here:
```
"vultr_startup_script_facts": [
{
"date_created": "2018-07-19 08:52:55",
"date_modified": "2018-07-19 08:52:55",
"id": 327140,
"name": "myteststartupscript",
"script": "#!/bin/bash\necho Hello World > /root/hello",
"type": "boot"
}
]
```
