[Enhancement] Add default avatar when profile image is not available (#188)

* Add default avatar when agent image is not available

* Remove fonts from avatar
Separate non-computed style values

app/javascript/dashboard/components/widgets/Avatar.vue

@@ -0,0 +1,80 @@
+<template>
+  <div
+    class="avatar-container"
+    :style="[style, customStyle]"
+    aria-hidden="true"
+  >
+    <span>{{ userInitial }}</span>
+  </div>
+</template>
+
+<script>
+export default {
+  name: 'Avatar',
+  props: {
+    username: {
+      type: String,
+    },
+    backgroundColor: {
+      type: String,
+    },
+    color: {
+      type: String,
+    },
+    customStyle: {
+      type: Object,
+    },
+    size: {
+      type: Number,
+      default: 40,
+    },
+    src: {
+      type: String,
+    },
+    rounded: {
+      type: Boolean,
+      default: true,
+    },
+  },
+  computed: {
+    style() {
+      return {
+        width: `${this.size}px`,
+        height: `${this.size}px`,
+        borderRadius: this.rounded ? '50%' : 0,
+        lineHeight: `${this.size + Math.floor(this.size / 20)}px`,
+        backgroundColor: this.backgroundColor,
+        fontSize: `${Math.floor(this.size / 2.5)}px`,
+        color: this.color,
+      };
+    },
+    userInitial() {
+      return this.initials || this.initial(this.username);
+    },
+  },
+  methods: {
+    initial(username) {
+      const parts = username ? username.split(/[ -]/) : [];
+      let initials = '';
+      for (let i = 0; i < parts.length; i += 1) {
+        initials += parts[i].charAt(0);
+      }
+      if (initials.length > 2 && initials.search(/[A-Z]/) !== -1) {
+        initials = initials.replace(/[a-z]+/g, '');
+      }
+      initials = initials.substr(0, 2).toUpperCase();
+      return initials;
+    },
+  },
+};
+</script>
+
+<style lang="scss" scoped>
+.avatar-container {
+  display: flex;
+  font-weight: bold;
+  align-items: center;
+  justify-content: center;
+  text-align: center;
+}
+</style>