views: Use bundle-detail for public URLs

views: Use bundle-detail for public URLs

In 'd1c605f', we reworked the 'bundle-list' view to use the new
'Bundle.get_mbox_url' function instead of the 'Bundle.public_url'.
However, these are not the same thing. The latter referred to the
'bundle-detail' view, while the former referred to the 'bundle-mbox'
view.

The easiest fix would be to simply revert that patch. However, it turns
out that 'public_url' isn't actually needed. Commit '5d0140ef' removed a
divide between public and non-public URLs for bundles, meaning we can
actually use an existing function - 'get_absolute_url' - instead.

This also presents the opportunity to clean up the 'bundle-list' page,
favouring a simple public/is-not-public marker and only a single URL.

Signed-off-by: Stephen Finucane <stephen@that.guru>
Fixes: d1c605f9 ("views: Stop using Bundle.public_url")
Closes-bug: #92