Setup Vue app for group transfer data page

What does this MR do and why?

Related to #386404

We are starting to build a dashboard to monitor egress data transfer. The first dashboard will be at the group level in Settings -> Usage quotas.

This MR sets up all of the Vue application boilerplate. In future MRs we will make a GraphQL query to get the data and then build out sections of this dashboard.

Behind the data_transfer_monitoring feature flag

Screenshots or screen recordings

Before	After - feature flag disabled	After - feature flag enabled

How to set up and validate locally

1. Enable the data_transfer_monitoring feature flag
   • bin/rails console
   • Feature.enable(:data_transfer_monitoring)
2. Navigate to a top level group -> Settings -> Usage quotas
3. Click on the Transfer tab

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.