Collapse aliases into parent site

[gearoidc]

I recently added about 8 aliases to a site and now my sites listing tab is suddenly crowded - it would be nice (for me anyway) to have a 'folder' like structure on sites where we can collapse alias'd sites into parent?

[gearoidc]

something like this from FlyEnv

[gearoidc]

This feature request would also be nice for above #1318