Add support for Navigation Beta 1+

I tested this out and I see one glaring difference between Gin 3.x-dev with this patch, and Claro:

With Claro/Olivero:

With Gin:

As you can see, Gin is for some reason not displaying the Shortcuts sub-menu. That's important for my project. Am I missing something here, or is there a bug in Gin?

Ah -- never mind. Gin moves the Shortcuts list to the top bar, which is a legitimate design decision.

Okay, I can't find anything to fault!

@phenaproxima I've updated the description to reflect that, sorry forgot to mention that.

Makes sense if it's an intentional design decision.

But the problem I'm having is the inconsistency. After all, the navigation will still appear when the front-end theme is active; elements should not move out of the navigation when viewing it in the frontend theme, because the navigation is fundamentally an administrative element of the page, regardless of theme.

Is there a way to make Gin not move the shortcuts around? If not, could that be added as a setting?

@phenaproxima no inconsistencies introduced here, rather eliminated as all our other navigation (toolbar) options use the same. You'll need our companion module (gin_toolbar) anyway to use Gin's option in your frontend theme.

OK, with some guidance from @saschaeggi I was able to confirm that, with Gin Toolbar installed, the shortcuts always appear in the top bar, even in the frontend theme. So indeed, no inconsistencies if everything's set up correctly.

As far as I can tell, this patch is good to go!

Automatically closed - issue fixed for 2 weeks with no activity.