Update editor tools to handle unlisted and listed versions

[eviljeff]

Part of #3477
Currently we have a single review page that shows all (non-beta) versions of an add-on and allows messages/feedback to be sent, and actions to be taken, on the latest version of the add-on. Access is gated on Addon.is_listed. With unlisted and listed versions on the same add-on we need to make some changes.

[eviljeff]

I guess we could hide the unlisted versions from the normal reviewers and pretend they don't exist but for unlisted reviews and staff it's going to get tricky.
Should we show all the versions in the review history? Sending any messages, etc, are usually linked to the latest version... which would be which? the last listed version? the last version from either channel?

[eviljeff]

@wagnerand suggested separate review pages or separate tabs on the same page. (the former is easier to implement)

[jvillalobos]

Using different pages makes sense to me.

[eviljeff]

@jvillalobos what should the behaviour be if there are no listed or no listed versions and you attempt to access the unlisted or listed review page? (i.e. you access /review and it only has unlisted versions, or visa versa). If you are staff/admin should it:

• 404?
• Show a review page but with no versions?
• redirect to the review page for the channel where there are versions?

If a normal reviewer accesses the /review page and the add-on only has unlisted versions should it:

• 404?
• Show a review page but with no versions?

[jvillalobos]

I think no versions in the first case, 404 in the second. @wagnerand, thoughts?

[wagnerand]

👍