Improve repo tooling (#398)

* add basic git files to root

* make server part of monorepo

* import promo

* import libraries base

* import docs

* import desktop

* move docs and promo

sites/promo/src/components/screenshot.tsx

@@ -0,0 +1,31 @@
+import { clsx } from 'clsx'
+
+export function Screenshot({
+  width,
+  height,
+  src,
+  className,
+}: {
+  width: number
+  height: number
+  src: string
+  className?: string
+}) {
+  return (
+    <div
+      style={{ '--width': width, '--height': height } as React.CSSProperties}
+      className={clsx(
+        className,
+        'relative aspect-[var(--width)/var(--height)] [--radius:var(--radius-xl)]',
+      )}
+    >
+      <div className="absolute -inset-(--padding) rounded-[calc(var(--radius)+var(--padding))] shadow-xs ring-1 ring-black/5 [--padding:--spacing(2)]" />
+      <img
+        alt=""
+        src={src}
+        className="h-full rounded-(--radius) shadow-2xl ring-1 ring-black/10"
+      />
+      <span className='absolute bottom-0 left-0 text-xs text-zinc-300 text-center bg-zinc-900 rounded-(--radius) px-1 py-0.5'>All games and other content shown in screenshots are examples, without actual content.</span>
+    </div>
+  )
+}