docs: add BannerMessage component

docs/src/components/BannerMessage/index.vue

@@ -0,0 +1,43 @@
+<template>
+  <g-link :class="`banner-message banner-message--${color}`" :to="to">
+    <slot />
+  </g-link>
+</template>
+
+<script>
+export default {
+  props: {
+    to: {
+      type: String,
+      required: true,
+    },
+
+    color: {
+      type: String,
+      default: 'black',
+    },
+  },
+}
+</script>
+
+<style lang="scss" scoped>
+.banner-message {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex: 0 0 auto;
+  padding: 0.65rem 1rem;
+  font-size: 0.85rem;
+  font-weight: 500;
+
+  &--black {
+    background-color: $colorBlack;
+    color: $colorWhite;
+  }
+
+  &--yellow {
+    background-color: $colorYellow;
+    color: $colorBlack;
+  }
+}
+</style>