always append uui-root and uui-text to storybook body

Author: nielslyngsoe

.storybook/preview-body.html

@@ -0,0 +1,4 @@
+<script>
+  document.body.classList.add('uui-root');
+  document.body.classList.add('uui-text');
+</script>

packages/uui-css/lib/guidelines.story.ts

@@ -5,7 +5,7 @@ export default {
 };
 
 export const Layout = () => html`
-  <article class="uui-root uui-text" style="max-width:580px;">
+  <article style="max-width:580px;">
     <div
       style="display:block; border-bottom: 1px solid var(--uui-color-cocoa-black); padding-top: var(--uui-size-layout-5); margin-bottom:var(--uui-size-layout-3); padding-bottom:var(--uui-size-layout-1);">
       <h1>Layout Style Guide</h1>
@@ -74,7 +74,7 @@ export const Layout = () => html`
 `;
 
 export const Typography = () => html`
-  <article class="uui-root uui-text" style="max-width:580px;">
+  <article style="max-width:580px;">
     <div
       style="display:block; border-bottom: 1px solid var(--uui-color-cocoa-black); padding-top: var(--uui-size-layout-5); margin-bottom:var(--uui-size-layout-3); padding-bottom:var(--uui-size-layout-1);">
       <h1>Typography Style Guide</h1>

packages/uui-css/lib/uui-css.story.ts

@@ -16,9 +16,7 @@ export default {
   },
 };
 
-export const Overview: Story = () => html` <article
-  class="uui-root uui-text"
-  style="max-width:580px;">
+export const Overview: Story = () => html` <article style="max-width:580px;">
   <h2>CSS</h2>
   <p>
     UUI-CSS package contains css files which can be included in your project or