Playbook that contain external references should be displayed and have clickable links

[MaartendeKruijf]

Is your feature request related to a problem? Please describe.
Playbooks in the GUI should display external reference they are present in the playbook.

    "external_references": [
        {
            "name": "TNO COSSAS",
            "description": "TNO COSSAS",
            "source": "TNO COSSAS",
            "url": "https://app.cymph.io/en/dashboard/editor/2878"
        }
    ],

Describe the solution you'd like
The reference should appear in the playbook details and should display the name, description, source and link, The link should be clickable to follow from a browser. If the link is too lang to display it should be truncated. When hovering it should be displayed. All text should be sanitised before displaying.

[antonatos]

The URL for Cymph should be "https://app.cymph.io/hub/"