Consolidate user avatar Vue logic

Creates 3 vue components:

1. user-avatar-link
2. user-avatar-image
3. user-avatar-svg

and implements them in several places.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/31017

• Port to EE
• Test each implementation manually

EE Compatible Branch: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1699

app/assets/javascripts/cycle_analytics/components/stage_production_component.js

@@ -23,8 +23,6 @@ global.cycleAnalytics.StageProductionComponent = Vue.extend({
         <li v-for="issue in items" class="stage-event-item">
           <div class="item-details">
             <user-avatar-image :src="issue.author.avatarUrl"/>
-
-            <img class="avatar" :src="issue.author.avatarUrl">
             <h5 class="item-title issue-title">
               <a class="issue-title" :href="issue.url">
                 {{ issue.title }}