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/vue_pipelines_index/components/pipeline_url.js

@@ -24,7 +24,6 @@ export default {
         class="js-pipeline-url-user"
         :href="pipeline.user.web_url"
         :img-src='pipeline.user.avatar_url'
-        :tooltip-container="'body'"
         :tooltip-text="pipeline.user.name">
       </user-avatar-link>
       <span