Themes: Merge layout/logged-out-design back into layout/logged-out

[ockham]

Ideally, there'd be only one logged-out layout (for consistency and ease of maintenance) which we could also use for server-side rendering. The main differences between the two logged-out layouts currently are:

• layout/logged-out-design uses ThemesHead
  • I'm wondering a bit if Helmet is really that beneficial. We have two levels of wrapping there (layout/head and my-sites/themes/head), and can't really leverage React anyway but need to toss around props and then extract those data again using rewind(). Wouldn't it be easier to just put that stuff into a Redux subtree? (And dispatch inside our controllers.) @mcsf?
• layout/logged-out uses the old notices store
  • I think there's a Redux store for them now, so that would need to be connected. Notices: Connect layout/logged-out to Redux notices #3083

[mcsf]

I'm wondering a bit if Helmet is really that beneficial. We have two levels of wrapping there (layout/head and my-sites/themes/head), and can't really leverage React anyway but need to toss around props and then extract those data again using rewind(). Wouldn't it be easier to just put that stuff into a Redux subtree? (And dispatch inside our controllers.) @mcsf?

As we discussed in a video walkthrough, sharing for posterity: Helmet would make a lot less sense if Calypso were already fully Redux'd and all state (sections, layout, routing?, etc.) lived in clear places of the global tree isomorphically. I think moving from Helmet to Redux will be a relatively straightforward task once we feel ready for it, so in the meantime we can benefit from the momentum advantage we're getting from Helmet.

[ockham]

Closing this issue since layout/logged-out doesn't exist anymore (see #2964). Maybe we should rename layout/logged-out-design to layout/logged-out tho.