ISTWCMS-5595: organizing the layout/_index.scss to make the site container display correctly

src/patterns/01-core/mixins/_uw-mixins.scss

@@ -19,7 +19,7 @@ $test-color-12: var(--green-5);
   word-wrap: break-word;
 }
 
-@mixin uw-contained-width($value:$max-width) {
+@mixin uw-contained-width($value:var(--layout-max-width)) {
   margin-left: auto;
   margin-right: auto;
   max-width: $value;

src/patterns/03-layouts/_index.scss

 // @file
 // Styles layouts
-@use '../01-core' as *;
+
 @use 'content/content' as *;
 @use 'footer/footer' as *;
 @use 'grid/grid' as *;
 @use 'header/header' as *;
 @use 'region/region' as *;
-@use 'layout/layout-base' as *;
 @use 'layout/layout' as *;
+@use 'layout/layout-base' as *;
+@use 'layout/layout--1-col/layout--1-col' as *;
+@use 'layout/layout--2-col/layout--2-col' as *;
+@use 'layout/layout--3-col/layout--3-col' as *;
+@use 'layout/layout--4-col/layout--4-col' as *;
+@use 'layout/layout--5-col/layout--5-col' as *;
+@use 'layout/layout--inverted-l-left/layout--inverted-l-left' as *;
+@use 'layout/layout--inverted-l-right/layout--inverted-l-right' as *;
 @use 'site-container/site-container' as *;
 @use 'site-footer/site-footer' as *;

src/patterns/03-layouts/layout/_layout-base.scss

 @use '../../01-core' as *;
-@use '../../03-layouts/layout/layout--1-col/layout--1-col' as *;
-@use '../../03-layouts/layout/layout--2-col/layout--2-col' as *;
-@use '../../03-layouts/layout/layout--3-col/layout--3-col' as *;
-@use '../../03-layouts/layout/layout--4-col/layout--4-col' as *;
-@use '../../03-layouts/layout/layout--5-col/layout--5-col' as *;
-@use '../../03-layouts/layout/layout--inverted-l-left/layout--inverted-l-left' as *;
-@use '../../03-layouts/layout/layout--inverted-l-right/layout--inverted-l-right' as *;
 
 .layout__region {
 

src/patterns/03-layouts/layout/_layout.twig

-{{ attach_library('uw_wcms_ohana/layout') }}
-
 {% set section_names = {
   1: 'first',
   2: 'second',

src/patterns/global.scss

@@ -5,3 +5,4 @@
 @use '01-core/props' as *;
 @use '01-core/utilities' as *;
 @use '01-core/elements' as *;
+@use '03-layouts' as *;