New extension point (for readme) in code overview

The readme files should be rendered in the code overview below
the file tree and not in a separate page. To render the readme file,
a new extension point was added. The order of items in the side
menu also got changed.

scm-ui/ui-components/src/index.ts

@@ -90,6 +90,7 @@ export * from "./devices";
 export { default as copyToClipboard } from "./CopyToClipboard";
 export { createA11yId } from "./createA11yId";
 export { useSecondaryNavigation } from "./useSecondaryNavigation";
+export { default as useScrollToElement } from "./useScrollToElement";
 
 export { default as comparators } from "./comparators";