Add copy link button on dashboards page

[fcollonval]

Is your feature request related to a problem? Please describe.

I did not find a easy way to obtain a shareable link for a dashboard (sorry if I miss a straightforward way). Maybe a copy shareable link feature on the dashboards page could be helpful.

Describe the solution you'd like

Describe alternatives you've considered

Background context

Configuration

[danlester]

This could definitely be made more obvious, but can you not just share the link to the dashboard as listed on the Dashboards list page?

e.g. https://myjupyterhub.net/hub/dashboards/test

This should redirect the user straight to the dashboard via JupyterHub login if necessary.

But a little icon to copy directly to the clipboard would be good.

Please let me know if I've misunderstood.