Add component API to docs (ex: props, events, slots)

src/routes/components/button.md

@@ -0,0 +1,14 @@
+---
+title: Button
+component: Button
+---
+
+<script lang="ts">
+    import Button from "$lib/components/Button.svelte";
+</script>
+
+<Button>Eat cake</Button>
+
+<Button size="sm" color="primary">Small piece</Button>
+
+<Button size="lg" color="danger">Big part</Button>