Document how to vue

What does this MR do?

Adding a new framework can be challenge even when we have documentation :) In order to make it easier this MR explains the concepts of Components, Store and Service and how they should be used when using Vue.js in GitLab.

@jschatz1 @fatihacet @iamphill can you please read it and see what can be improved/changed/added? Thank you! ✨

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together