add a preview-function for archive pages

[thebootable]

Is your feature request related to a problem? Please describe.
When creating a new campaign there is the option to add the camapaign to the archive. I then have the option to choose a) a separate template and b) specific dummy-metadata as placeholders. But I can't preview how the page is displayed and have to wait for it to be published before I can fix any errors I might have made with e.g. the dummy-metadata.

Describe the solution you'd like
I think it would be helpful if there was a "preview" function in the archive section similar to the content-page where I write my message. This helps with identifying any issues before publishing the message and making sure it is shown as intended and I have chosen the right template and dummy-metadata.