feat: add Grid component

src/Grid/Grid.svelte

@@ -0,0 +1,25 @@
+<script>
+  export let as = false;
+  export let condensed = false;
+  export let fullWidth = false;
+
+  $: props = {
+    ...$$restProps,
+    class: [
+      $$restProps.class,
+      "bx--grid",
+      condensed && "bx--grid--condensed",
+      fullWidth && "bx--grid--full-width"
+    ]
+      .filter(Boolean)
+      .join(" ")
+  };
+</script>
+
+{#if as}
+  <slot {props} />
+{:else}
+  <div {...props}>
+    <slot />
+  </div>
+{/if}