Add option to start private chat

By clicking on avatar. Issue #101.

src/components/messages/AvatarOperations.vue

@@ -0,0 +1,37 @@
+<template>
+  <div
+    :class="{
+      'avatar-operations': true,
+      incoming: incoming,
+      outgoing: !incoming,
+    }"
+  >
+    <v-btn v-if="incoming" text @click.stop="startPrivateChat" class="ma-0 pa-0"
+      >Private chat with this user</v-btn
+    >
+  </div>
+</template>
+
+<script>
+import messageMixin from "./messageMixin";
+
+export default {
+  mixins: [messageMixin],
+  mounted() {
+      // Any items to show?
+      if (this.room && this.event && this.$matrix.isDirectRoomWith(this.room, this.event.getSender())) {
+        this.$emit("close");
+      }
+  },
+  methods: {
+    startPrivateChat() {
+      this.$emit("close");
+      this.$emit("start-private-chat", { event: this.event });
+    },
+  },
+};
+</script>
+
+<style lang="scss">
+@import "@/assets/css/chat.scss";
+</style>