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/environments/components/environment_item.js

@@ -485,10 +485,10 @@ export default {
           by
           <user-avatar-link
             class="js-deploy-user-container"
-            :title='deploymentUser.username'
             :href="deploymentUser.web_url"
             :img-src='deploymentUser.avatar_url'
-            :img-alt='userImageAltDescription'>
+            :img-alt='userImageAltDescription'
+            :tooltip-text='deploymentUser.username'>
           </user-avatar-link>
         </span>
       </td>