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_code_component.js

@@ -11,6 +11,7 @@ global.cycleAnalytics.StageCodeComponent = Vue.extend({
     stage: Object,
   },
   components: {
+    'user-avatar-image': UserAvatarImage,
   },
   template: `
     <div>