[BUG] no feedback when importing single object in device import

[DumpySquare]

When importing a single object, not an array, it does not do anything. Some logging feedback should steer the user to the documentation or that imports need to be an array.

https://f5devcentral.github.io/vscode-f5/#/device_importing

[DumpySquare]

Need to add some logic to support single object import and provide better feedback with errors

• acceptable inputs:
• • 'admin@1.1.1.1'
• • ['admin@1.1.1.1', 'usr1@2.2.2.2:8443', ...]
• • [{ device: 'admin@4.4.4.4', password: 'pizzaTower', provider: 'tmos' }, ...]

need to support a single object

    {
        "device": "dude@2.1.3.4",
        "password": "coolness",
        "provider": "tmos"
    }

[DumpySquare]

Single object support has been added in 3.15 (pending release). I did not see any other possible json inputs to extend the error messaging.