New version update submission flow for Listed and Unlisted

[jvillalobos]

Part of #3477

The add-on version update submission flow will have a look and feel more consistent with the new add-on submission flow. Also, at this point it will be possible to choose a different channel for new versions, which means channel will no longer be set based on is_listed. UX for this new flow is in #192.

[eviljeff]

Three parts to the QA here:

1. Check the new addon upload flow still works as expected - this patch changes the code used for new addon upload but functionally should work the same.
2. Check the (new) new version upload flow is working - Enable waffle switch step-version-upload and upload a new version via devhub using any of the usual links. You will only be able to upload a listed version on a listed addon, and an unlisted version on an unlisted addon.
3. [Advanced level] mixed unlisted and listed versions. (see next comment)

[eviljeff]

Mixed Unlisted & Listed Versions

Optional QA for the 2016-11-17 push but it would be good to know sooner rather than later if the flow is broken at least.

Don't try this on prod as the rest of the site can't handle mixed unlisted and listed versions on the same add-on yet. You will need to enable waffle switch mixed-listed-unlisted.

The key differences are the upload flow contains a link under the channel description to change it (goes back to a distribution step). If you upload an unlisted version on a listed add-on not a great deal different happens during the flow; if you upload a listed version on an unlisted add-on then the details step should appear like you see during new add-on submission to collect missing metadata.

Right now there isn't a way to identify the different channels of the versions anywhere, but #3482 will add this.

[ValentinaPC]

@eviljeff : at point 2, in your comment, you wanted to say unlisted version on unlisted add-on , yes? Thanks!

[eviljeff]

@ValentinaPC yes, I did. corrected.

[ValentinaPC]

This can be marked as verified fixed, because all above bugs were fixed and verified.
Extra QA was made on this part, an separate issues were logged.