Recursively fetch repos from client side

[gdbroman]

We're currently fetching all of a user's GitHub repositories and their directories before they load the GitHub settings page.

This leads to a lot of combinations, forcing us to cap the search depth to 2 directories per repository.

A more efficient strategy would be to only fetch repos server side and then only fetch the selected repos directories when the select dropdown is clicked/opened. Alternatively fetch repos client side too.