Feature req - see a real-time list of intercept previews on the /intercepts base page

[sebhulse]

Is your feature request related to a problem? Please describe.
This feature request is related to this 'bug report' issue I raised: #495

Describe the solution you'd like
To be able to use the localhost:3883/intercepts page route to see a real-time updated list-view of all intercept email previews which have been created.

Describe alternatives you've considered
A fix to the bug where intercept redirects are not being initiated from a container would be nice but this could be a good middle-ground.

Additional context
It could have the same layout as the preview page, but just display a list of the intercept previews on the left in a list-view, and an enlarged view of the selected preview in the main area.