Add .container-fluid variation for full-width containers and layouts

/cc #10711 #9862

less/grid.less

@@ -2,7 +2,11 @@
 // Grid system
 // --------------------------------------------------
 
-// Set the container width, and override it for fixed navbars in media queries
+
+// Container widths
+//
+// Set the container width, and override it for fixed navbars in media queries.
+
 .container {
   .container-fixed();
 
@@ -17,12 +21,30 @@
   }
 }
 
-// mobile first defaults
+
+// Fluid container
+//
+// Utilizes the mixin meant for fixed width containers, but without any defined
+// width for fluid, full width layouts.
+
+.container-fluid {
+  .container-fixed();
+}
+
+
+// Row
+//
+// Rows contain and clear the floats of your columns.
+
 .row {
   .make-row();
 }
 
+
+// Columns
+//
 // Common styles for small and large grid columns
+
 .make-grid-columns();
 
 
@@ -76,4 +98,3 @@
   .make-grid(@grid-columns, lg, push);
   .make-grid(@grid-columns, lg, offset);
 }
-

less/navbar.less

@@ -93,14 +93,17 @@
 //
 // When a container is present, change the behavior of the header and collapse.
 
-.container > .navbar-header,
-.container > .navbar-collapse {
-  margin-right: -@navbar-padding-horizontal;
-  margin-left:  -@navbar-padding-horizontal;
+.container,
+.container-fluid {
+  > .navbar-header,
+  > .navbar-collapse {
+    margin-right: -@navbar-padding-horizontal;
+    margin-left:  -@navbar-padding-horizontal;
 
-  @media (min-width: @grid-float-breakpoint) {
-    margin-right: 0;
-    margin-left:  0;
+    @media (min-width: @grid-float-breakpoint) {
+      margin-right: 0;
+      margin-left:  0;
+    }
   }
 }
 
@@ -159,7 +162,8 @@
   }
 
   @media (min-width: @grid-float-breakpoint) {
-    .navbar > .container & {
+    .navbar > .container &,
+    .navbar > .container-fluid & {
       margin-left: -@navbar-padding-horizontal;
     }
   }