feat(Forms): add Value.Upload component (#4233)

Adds Value.Upload component

---------

Co-authored-by: Tobias Høegh <tobias@tujo.no>

packages/dnb-design-system-portal/src/docs/uilib/components/upload/Examples.tsx

@@ -13,7 +13,7 @@ import {
   Upload,
 } from '@dnb/eufemia/src'
 
-const createMockFile = (name: string, size: number, type: string) => {
+export function createMockFile(name: string, size: number, type: string) {
   const file = new File([], name, { type })
   Object.defineProperty(file, 'size', {
     get() {

packages/dnb-design-system-portal/src/docs/uilib/extensions/forms/Value/Upload.mdx

@@ -0,0 +1,26 @@
+---
+title: 'Upload'
+description: '`Value.Upload` is a value component for displaying a list of files.'
+componentType: 'feature-value'
+showTabs: true
+tabs:
+  - title: Info
+    key: '/info'
+  - title: Demos
+    key: '/demos'
+  - title: Properties
+    key: '/properties'
+breadcrumb:
+  - text: Forms
+    href: /uilib/extensions/forms/
+  - text: Value
+    href: /uilib/extensions/forms/Value/
+  - text: Upload
+    href: /uilib/extensions/forms/Value/Upload/
+---
+
+import Info from 'Docs/uilib/extensions/forms/Value/Upload/info'
+import Demos from 'Docs/uilib/extensions/forms/Value/Upload/demos'
+
+<Info />
+<Demos />