Make os and host attributes reference the software SCO

[Harmedox]

Similar to #1377, os and host attributes can be better represented using the software SCO.

For example, go from:

"0": {
        "type": "x-oca-asset",
        "hostname": "thl-win",
        "os_name": "Windows Server 2019 Standard",
        "os_platform":"windows",
        "os_version":"10.0",
        ...
}

to:

"0": {
        "type": "software",
        "name": "Windows Server 2019 Standard",
        "version": "10.0",
        "vendor": "windows"
},
"1": {
        "type": "x-oca-asset",
        "hostname": "thl-win",
        "os_ref": "0",
        ...
},
    
    ...