Move #mw-panel into #mw-navigation

Not only might this make more sense from an accessibility standpoint
(because sidebar is also part of navigation and there is a heading with
that name), but it should also hide the sidebar when printing as there
are core styles that hide #mw-navigation.

[1] 3b381b71e9/resources/src/mediawiki.skinning/commonPrint.css (L31)

Bug: T265217
Change-Id: I7f936defa177ba172e4253ee6450040ffa52e257

includes/templates/Navigation.mustache

@@ -1,5 +1,6 @@
 <div id="mw-navigation">
 	<h2>{{msg-navigation-heading}}</h2>
+	{{#data-portlets-sidebar}}{{>Sidebar}}{{/data-portlets-sidebar}}
 	<div id="mw-head">
 		<div class="mw-article-toolbar-container">
 			{{#data-portlets}}

includes/templates/skin.mustache

@@ -43,7 +43,6 @@
 {{>Header}}
 
 <div class="mw-workspace-container">
-	{{#data-portlets-sidebar}}{{>Sidebar}}{{/data-portlets-sidebar}}
 	{{>Navigation}}
 	<div class="mw-content-container">
 {{! `role` is unnecessary but kept to support selectors in any gadgets or user styles. }}