Add docs button to the API-key connect dialog

The Add Source card links to a connector's docs, but the API-key
connect dialog did not, so a user filling in an API key had no path
to the setup instructions. Add a "Documentation" button to the dialog
footer, styled like Cancel and on the left of the Cancel/Connect row,
shown only when the provider has a docs page.

Extract the rendering into a shared ConnectorDocumentationLink
component with a link/button variant (the card keeps the quiet link,
the dialog uses the button) and give DialogFooter an optional start
slot for left-aligned footer content.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

packages/ui/src/Molecules/Dialog/Dialog.tsx

@@ -195,19 +195,27 @@ export function DialogFooter({
   children,
   exitLabel,
   className,
+  start,
 }: {
   children?: ReactNode;
   exitLabel?: string;
   className?: string;
+  // Optional content aligned to the footer's left edge (e.g. a documentation
+  // link), on the same line as the Cancel/confirm buttons. When set, the footer
+  // switches to justify-between; otherwise it keeps the default right alignment.
+  start?: ReactNode;
 }) {
   const { __ } = useTranslate();
   const { footer } = dialog();
   return (
-    <footer className={footer({ className })}>
-      <Close asChild>
-        <Button variant="secondary">{exitLabel ?? __("Cancel")}</Button>
-      </Close>
-      {children}
+    <footer className={footer({ className: clsx(start != null && "justify-between", className) })}>
+      {start != null && <div className="flex items-center gap-2">{start}</div>}
+      <div className="flex items-center gap-2">
+        <Close asChild>
+          <Button variant="secondary">{exitLabel ?? __("Cancel")}</Button>
+        </Close>
+        {children}
+      </div>
     </footer>
   );
 }