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

spec/javascripts/vue_shared/components/user_avatar_link_spec.js

@@ -51,7 +51,7 @@ describe('User Avatar Link Component', function () {
   });
   it('should include props in the rendered output', function () {
-    _.each(this.propsData, (val, key) => {
+    _.each(this.propsData, (val) => {
       expect(this.userAvatarLink.$el.outerHTML).toContain(val);
     });
   });