Campaign file preview should provide more details

[sachajudd]

I can't seem to find any designs for this so @silverstripeux to advise. From previous conversations we think the preview is supposed to have the title and thumbnail but with a link to edit it in the files area.

Main Campaign designs: https://projects.invisionapp.com/dsm/silver-stripe/silver-stripe/folder/components/5c68f96ffb26bb0018525d1c?frame-cb=1591311648699

[clarkepaul]

FYI the direction of where this should end up is to replicate the file edit panel, a transition could be to show that info as readonly as placement content is the type of information that should be reviewed prior to publishing the campaign. As a first step, it should at least have the image and title displayed nicely.