Hosts tab view in WebUI is broken when the Rest-API returns partly invalid resonse data

The Hosts tab view in the WebUI is broken when the REST-API returns invalid response data, e.g.

{
    "count": 2, 
    "next": null, 
    "previous": null, 
    "results": [
        {
            "id": 1, 
            "name": "oatrusty", 
            "url": "http://192.168.10.102:8000/api/hosts/1", 
            ...
            "oa_version": {
                "package": {
                    "VERSION": "2.0.18"
                }
            }
        }, 
        "" <--- No JSON object for the remote host
    ]
}

This especially happens when the remote node API URL is not correct or the request has been failed in general.

Currently the user does not get any hint what has happened because the oA REST Multinode API Implementation does not log any error.

The bugfix will include the following improvements/fixes:

• Add more logging to provide helpful information what has happended when a remote request has been failed.
• Harden the WebUI to do not break when invalid response data is processed.
• Only useful tabs will be displayed in the below view when a disk/pool/volume is selected. Tabs that will fail to display valid data (e.g. because of invalid data from the REST-API call) will be hidden.
• The error message will be displayed in the tab view of the selected item, see screenshots.