Convert admin/users view - create Vue app wrapper

Problem to solve

Create a Vue application wrapper that consumes the @users data.

See audit events as an example.

Implementation plan

• Create an AdminUsers application wrapper
• Add application entry point to app/views/admin/users/index.html.haml and pass the @users array #285103 (closed)
• Initialize app in app/assets/javascripts/pages/admin/users/index.js