Merge port scripts and host scripts

[p-l-]

Managing both port and host scripts makes the code more complicated and, more importantly, make some request we make less efficient (because less capable of using MongoDB indexes).

We should either manage all scripts in a central list of nested documents:

{
    "ports": [{"proto": "tcp", "port": 80, [...]}, [...]],
    "scripts": [
        {"port": 80, "proto": "tcp", "id": "http-title", "output": [...]},
        {"host": True, "id": "firewalk", "output": [...]},
    ],
}

Or create a fake nested document in ports array:

{
    "ports": [
        {"proto": "tcp", "port": 80, "scripts": [{"id": "http-title", "output": [...]}, [...]] [...]},
        {"host": True, "scripts": [{"id": "firewalk", "output": [...]}, [...]]},
    ],
}