Improved "create room" flow

Still need to implement the "add friends" screen.

src/components/CreatedRoomWelcomeHeader.vue

@@ -0,0 +1,25 @@
+<template>
+  <div class="created-room-welcome-header">
+    <div class="h4">Welcome!</div>
+    <div class="mt-2">Here are a few things to know about your group:</div>
+    <div class="mt-2" v-if="roomJoinRule == 'public'">Anyone can join by opening this link: {{ publicRoomLink }}</div>
+    <div class="mt-2" v-else-if="roomJoinRule == 'invite'">Only people you invite can join.</div>
+    <div class="mt-2">You can change 'join permissions' and 'message history' at any time in the group settings.</div>
+    <div class="text-right">
+      <v-btn text @click.stop="$emit('close')">Got it</v-btn>
+    </div>
+  </div>
+</template>
+
+<script>
+import roomInfoMixin from "./roomInfoMixin";
+
+export default {
+  name: "CreatedRoomWelcomeHeader",
+  mixins: [roomInfoMixin],
+};
+</script>
+
+<style lang="scss">
+@import "@/assets/css/chat.scss";
+</style>