Improve File Browser performance

When navigating around directories in the file browser (https://gitlab.com/gitlab-org/gitlab-ce/tree/master), the experience feels a bit sluggish.

This is partly due to us doing full page reloads when clicking a directory.

For reference, BitBucket does a very good job at this:

Screen_Recording_2019-04-03_at_8.02.30_PM

Possible Solutions

As discussed in Slack: Using a Vue component here and making the requests async will help lower the latency but we might also need to do improve caching here.